Skip to main content

GMAB 6-K

Genmab A/S (GMAB)

6-K 2025-03-31 For: 2025-03-31
View Original
Added on April 08, 2026

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549


FORM 6-K


REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE MONTH OF MARCH 2025


COMMISSION FILE NUMBER 001-38976

Genmab A/S
(Exact name of Registrant as specified in its charter)

Carl Jacobsens Vej 30

2500 Valby

Denmark

+45 70 20 27 28
(Address of principal executive offices)


Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F ⌧ Form 40-F ◻

This report on Form 6-K shall be deemed to be incorporated by reference in Genmab A/S’s registration statements on Form S-8 (File No. 333-232693, 333-253519, 333-262970, 333-277273 and 333-284876) and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

nthony
GENMAB A/S
BY: /s/ Anthony Pagano
Name: Anthony Pagano
Title: Executive Vice President & Chief Financial Officer

DATE: MARCH 31, 2025

EXHIBIT INDEX

O
Exhibit Description of Exhibit
99.1 Company Announcement Dated March 31, 2025: Transactions in Connection with Share Buy-back Program
99.1(a) Appendix: Share Buy-Back Program Transactions March 26 to 28, 2025

Exhibit 99.1

Graphic

Transactions in connection with share buy-back program

Company Announcement

COPENHAGEN, Denmark; March 31, 2025 – Genmab A/S (Nasdaq: GMAB). On March 25, 2025, Genmab announced the initiation of a share buy-back program to repurchase up to 2.2 million shares to reduce capital and to honor our commitments under the Restricted Stock Unit program. The share buy-back program is expected to be completed no later than July 10, 2025.

The following transactions were executed under the program from March 26 to March 28, 2025:

Trading Platform No. of shares Average price (DKK) Total value (DKK)
March 26, 2025 XCSE 45,467 1,357.43
BCXE 21,311 1,357.41
AQEU 4,148 1,359.16
TQEX 4,174 1,356.43
Total 75,100 1,357.47 101,945,764.19
March 27, 2025 XCSE 48,249 1,380.52
BCXE 23,000 1,380.11
AQEU 4,357 1,382.59
TQEX 4,472 1,378.49
Total 80,078 1,380.40 110,539,671.20
March 28, 2025 XCSE 46,924 1,371.40
BCXE 23,961 1,371.22
AQEU 2,693 1,371.96
TQEX 4,800 1,371.78
Total 78,378 1,371.39 107,486,507.58
Total 233,556 319,971,942.97

Details of each transaction are included as an appendix to this announcement.

Following these transactions, Genmab holds 2,771,544 shares as treasury shares, corresponding to 4.19% of the total share capital and voting rights.

The share buy-back program is undertaken in accordance with Regulation (EU) No. 596/2014 (‘MAR’) and the Commission Delegated Regulation (EU) 2016/1052, also referred to as the “Safe Harbour Regulation.” Further details on the terms of the share buy-back program can be found in our company announcement no. 14 dated March 25, 2025.

About Genmab

Genmab is an international biotechnology company with a core purpose of guiding its unstoppable team to strive toward improving the lives of patients with innovative and differentiated antibody therapeutics. For more than 25 years, its passionate, innovative and collaborative team has invented next-generation antibody technology platforms and leveraged translational, quantitative and data sciences, resulting in a proprietary pipeline including bispecific T-cell engagers, antibody-drug conjugates, next-generation immune checkpoint modulators and effector function-enhanced antibodies. By 2030, Genmab’s vision is to transform the lives of people with cancer and other serious diseases with knock-your-socks-off (KYSO) antibody medicines^®^.

Genmab A/S Tel: +45 7020 2728 Company Announcement no. 15
Carl Jacobsens Vej 30 Fax: +45 7020 2729 Page 1/2
2500 Valby, Denmark www.genmab.com CVR no. 2102 3884
LEI Code 529900MTJPDPE4MHJ122

Graphic

Transactions in connection with share buy-back program

Established in 1999, Genmab is headquartered in Copenhagen, Denmark, with international presence across North America, Europe and Asia Pacific. For more information, please visit Genmab.com and follow us on LinkedIn and X.

Contact:
Marisol Peron, Senior Vice President, Global Communications & Corporate Affairs

T: +1 609 524 0065; E: [email protected]

Andrew Carlsen, Vice President, Head of Investor Relations

T: +45 3377 9558; E: [email protected]


This Company Announcement contains forward looking statements. The words “believe,” “expect,” “anticipate,” “intend” and “plan” and similar expressions identify forward looking statements. Actual results or performance may differ materially from any future results or performance expressed or implied by such statements. The important factors that could cause our actual results or performance to differ materially include, among others, risks associated with pre-clinical and clinical development of products, uncertainties related to the outcome and conduct of clinical trials including unforeseen safety issues, uncertainties related to product manufacturing, the lack of market acceptance of our products, our inability to manage growth, the competitive environment in relation to our business area and markets, our inability to attract and retain suitably qualified personnel, the unenforceability or lack of protection of our patents and proprietary rights, our relationships with affiliated entities, changes and developments in technology which may render our products or technologies obsolete, and other factors. For a further discussion of these risks, please refer to the risk management sections in Genmab’s most recent financial reports, which are available on www.genmab.com and the risk factors included in Genmab’s most recent Annual Report on Form 20-F and other filings with the U.S. Securities and Exchange Commission (SEC), which are available at www.sec.gov. Genmab does not undertake any obligation to update or revise forward looking statements in this Company Announcement nor to confirm such statements to reflect subsequent events or circumstances after the date made or in relation to actual results, unless required by law.


Genmab A/S and/or its subsidiaries own the following trademarks: Genmab^®^; the Y-shaped Genmab logo^®^; Genmab in combination with the Y-shaped Genmab logo^®^; HuMax^®^; DuoBody^®^; HexaBody^®^; DuoHexaBody^®^, HexElect^®^ and KYSO^®^.

Genmab A/S Tel: +45 7020 2728 Company Announcement no. 15
Carl Jacobsens Vej 30 Fax: +45 7020 2729 Page 2/2
2500 Valby, Denmark www.genmab.com CVR no. 2102 3884
LEI Code 529900MTJPDPE4MHJ122

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

Issuer Date Time CET Quantity Price (DKK) Venue
GENMAB A/S 26-Mar-25 9:30:18 AM 70 1337.00 XCSE
GENMAB A/S 26-Mar-25 9:30:42 AM 42 1338.00 XCSE
GENMAB A/S 26-Mar-25 9:30:42 AM 67 1338.00 CEUX
GENMAB A/S 26-Mar-25 9:32:04 AM 56 1338.50 XCSE
GENMAB A/S 26-Mar-25 9:32:04 AM 68 1339.50 XCSE
GENMAB A/S 26-Mar-25 9:32:04 AM 1 1339.50 XCSE
GENMAB A/S 26-Mar-25 9:32:04 AM 4 1338.50 XCSE
GENMAB A/S 26-Mar-25 9:32:04 AM 24 1339.00 CEUX
GENMAB A/S 26-Mar-25 9:32:04 AM 39 1338.00 CEUX
GENMAB A/S 26-Mar-25 9:32:04 AM 63 1339.00 TQEX
GENMAB A/S 26-Mar-25 9:32:04 AM 68 1338.00 TQEX
GENMAB A/S 26-Mar-25 9:32:04 AM 64 1338.00 AQEU
GENMAB A/S 26-Mar-25 9:32:04 AM 71 1339.00 AQEU
GENMAB A/S 26-Mar-25 9:34:10 AM 30 1339.00 CEUX
GENMAB A/S 26-Mar-25 9:36:02 AM 18 1340.50 CEUX
GENMAB A/S 26-Mar-25 9:36:02 AM 37 1340.50 CEUX
GENMAB A/S 26-Mar-25 9:36:02 AM 32 1340.50 AQEU
GENMAB A/S 26-Mar-25 9:36:04 AM 72 1340.00 XCSE
GENMAB A/S 26-Mar-25 9:36:04 AM 7 1340.00 TQEX
GENMAB A/S 26-Mar-25 9:36:04 AM 16 1340.00 TQEX
GENMAB A/S 26-Mar-25 9:36:06 AM 26 1339.50 CEUX
GENMAB A/S 26-Mar-25 9:36:06 AM 12 1339.50 CEUX
GENMAB A/S 26-Mar-25 9:39:00 AM 23 1339.50 AQEU
GENMAB A/S 26-Mar-25 9:39:01 AM 23 1339.00 TQEX
GENMAB A/S 26-Mar-25 9:39:11 AM 15 1338.50 XCSE
GENMAB A/S 26-Mar-25 9:39:19 AM 54 1338.50 XCSE
GENMAB A/S 26-Mar-25 9:39:32 AM 22 1338.00 CEUX
GENMAB A/S 26-Mar-25 9:39:32 AM 3 1338.00 CEUX
GENMAB A/S 26-Mar-25 9:39:33 AM 75 1338.00 XCSE
GENMAB A/S 26-Mar-25 9:39:33 AM 53 1338.50 CEUX
GENMAB A/S 26-Mar-25 9:40:16 AM 39 1337.00 XCSE
GENMAB A/S 26-Mar-25 9:40:16 AM 3 1337.00 CEUX
GENMAB A/S 26-Mar-25 9:41:21 AM 72 1337.00 XCSE
GENMAB A/S 26-Mar-25 9:41:21 AM 34 1337.00 CEUX
GENMAB A/S 26-Mar-25 9:41:24 AM 33 1336.00 CEUX
GENMAB A/S 26-Mar-25 9:41:24 AM 14 1336.00 CEUX
GENMAB A/S 26-Mar-25 9:41:24 AM 23 1336.00 TQEX
GENMAB A/S 26-Mar-25 9:42:39 AM 73 1335.50 XCSE
GENMAB A/S 26-Mar-25 9:42:39 AM 48 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:42:39 AM 27 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:42:39 AM 44 1335.00 CEUX
GENMAB A/S 26-Mar-25 9:43:04 AM 71 1333.50 XCSE
GENMAB A/S 26-Mar-25 9:43:04 AM 64 1333.50 CEUX

1

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 9:43:27 AM 71 1332.50 XCSE
GENMAB A/S 26-Mar-25 9:43:27 AM 49 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:43:29 AM 1 1331.50 XCSE
GENMAB A/S 26-Mar-25 9:44:14 AM 8 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:44:14 AM 24 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:45:04 AM 71 1334.00 CEUX
GENMAB A/S 26-Mar-25 9:46:05 AM 73 1334.00 CEUX
GENMAB A/S 26-Mar-25 9:47:01 AM 23 1334.00 XCSE
GENMAB A/S 26-Mar-25 9:47:12 AM 12 1334.00 XCSE
GENMAB A/S 26-Mar-25 9:47:12 AM 11 1334.00 XCSE
GENMAB A/S 26-Mar-25 9:47:28 AM 20 1334.00 CEUX
GENMAB A/S 26-Mar-25 9:48:01 AM 23 1335.00 XCSE
GENMAB A/S 26-Mar-25 9:48:01 AM 4 1335.00 XCSE
GENMAB A/S 26-Mar-25 9:48:01 AM 74 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:48:26 AM 2 1334.50 CEUX
GENMAB A/S 26-Mar-25 9:48:50 AM 12 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:48:50 AM 58 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:49:03 AM 73 1334.50 XCSE
GENMAB A/S 26-Mar-25 9:49:27 AM 29 1334.50 CEUX
GENMAB A/S 26-Mar-25 9:49:28 AM 52 1334.00 CEUX
GENMAB A/S 26-Mar-25 9:49:28 AM 23 1334.00 TQEX
GENMAB A/S 26-Mar-25 9:50:01 AM 1 1333.50 XCSE
GENMAB A/S 26-Mar-25 9:50:01 AM 69 1333.50 XCSE
GENMAB A/S 26-Mar-25 9:50:02 AM 18 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:50:02 AM 42 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:50:02 AM 21 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:50:02 AM 4 1332.50 XCSE
GENMAB A/S 26-Mar-25 9:50:02 AM 42 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:50:02 AM 27 1333.00 TQEX
GENMAB A/S 26-Mar-25 9:51:32 AM 42 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:51:32 AM 30 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:51:32 AM 14 1332.50 XCSE
GENMAB A/S 26-Mar-25 9:51:32 AM 11 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:51:32 AM 73 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:51:32 AM 23 1333.00 TQEX
GENMAB A/S 26-Mar-25 9:51:49 AM 27 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:51:54 AM 6 1332.50 XCSE
GENMAB A/S 26-Mar-25 9:52:06 AM 47 1332.50 XCSE
GENMAB A/S 26-Mar-25 9:52:41 AM 37 1332.00 XCSE
GENMAB A/S 26-Mar-25 9:52:41 AM 74 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:52:41 AM 5 1331.50 TQEX
GENMAB A/S 26-Mar-25 9:52:44 AM 9 1331.50 TQEX
GENMAB A/S 26-Mar-25 9:53:03 AM 2 1331.50 TQEX
GENMAB A/S 26-Mar-25 9:53:17 AM 11 1331.50 TQEX
GENMAB A/S 26-Mar-25 9:54:27 AM 16 1332.50 CEUX

2

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 9:54:29 AM 1 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:54:46 AM 42 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:54:46 AM 12 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:54:46 AM 30 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:54:46 AM 7 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:54:46 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:54:48 AM 9 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:54:48 AM 1 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:54:48 AM 31 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:54:48 AM 28 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:54:48 AM 18 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:55:15 AM 36 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:55:26 AM 2 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:05 AM 72 1332.00 XCSE
GENMAB A/S 26-Mar-25 9:56:05 AM 72 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:56:05 AM 29 1332.00 TQEX
GENMAB A/S 26-Mar-25 9:56:26 AM 1 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:56:27 AM 1 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:56:41 AM 23 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:41 AM 9 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:41 AM 6 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:41 AM 17 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:41 AM 8 1333.00 CEUX
GENMAB A/S 26-Mar-25 9:56:44 AM 58 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:56:54 AM 50 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 8 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:54 AM 33 1333.00 TQEX
GENMAB A/S 26-Mar-25 9:56:55 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:55 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 53 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 21 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 60 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:57 AM 12 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:58 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:58 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:58 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:58 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:59 AM 11 1333.00 XCSE

3

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 9:56:59 AM 72 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:59 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:59 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:56:59 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 75 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:00 AM 44 1333.00 TQEX
GENMAB A/S 26-Mar-25 9:57:01 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:01 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:01 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:01 AM 74 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:02 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:02 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:02 AM 3 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:02 AM 20 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:04 AM 13 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:04 AM 9 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:04 AM 1 1333.00 XCSE
GENMAB A/S 26-Mar-25 9:57:07 AM 15 1332.50 CEUX
GENMAB A/S 26-Mar-25 9:57:28 AM 73 1332.00 XCSE
GENMAB A/S 26-Mar-25 9:57:28 AM 24 1332.00 TQEX
GENMAB A/S 26-Mar-25 9:57:54 AM 2 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:58:26 AM 5 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:59:14 AM 36 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:59:14 AM 27 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:59:34 AM 26 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:59:34 AM 7 1332.00 CEUX
GENMAB A/S 26-Mar-25 9:59:40 AM 25 1331.00 XCSE
GENMAB A/S 26-Mar-25 9:59:40 AM 71 1331.50 CEUX
GENMAB A/S 26-Mar-25 9:59:43 AM 47 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:00:04 AM 20 1330.50 CEUX
GENMAB A/S 26-Mar-25 10:00:04 AM 14 1330.50 CEUX
GENMAB A/S 26-Mar-25 10:00:04 AM 35 1330.50 CEUX
GENMAB A/S 26-Mar-25 10:00:04 AM 10 1330.50 TQEX
GENMAB A/S 26-Mar-25 10:00:04 AM 18 1330.50 TQEX
GENMAB A/S 26-Mar-25 10:00:06 AM 2 1330.50 TQEX
GENMAB A/S 26-Mar-25 10:00:18 AM 71 1329.50 XCSE
GENMAB A/S 26-Mar-25 10:01:22 AM 39 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:01:23 AM 42 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:01:23 AM 8 1331.00 XCSE

4

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:01:23 AM 8 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:02:00 AM 4 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:02:00 AM 42 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:02:11 AM 23 1331.00 XCSE
GENMAB A/S 26-Mar-25 10:02:34 AM 72 1330.50 XCSE
GENMAB A/S 26-Mar-25 10:02:34 AM 71 1330.50 CEUX
GENMAB A/S 26-Mar-25 10:02:34 AM 33 1330.50 TQEX
GENMAB A/S 26-Mar-25 10:02:55 AM 43 1329.50 CEUX
GENMAB A/S 26-Mar-25 10:02:55 AM 28 1329.50 CEUX
GENMAB A/S 26-Mar-25 10:02:58 AM 10 1329.50 XCSE
GENMAB A/S 26-Mar-25 10:02:58 AM 59 1329.50 XCSE
GENMAB A/S 26-Mar-25 10:02:58 AM 23 1329.50 TQEX
GENMAB A/S 26-Mar-25 10:03:45 AM 34 1329.00 XCSE
GENMAB A/S 26-Mar-25 10:03:45 AM 8 1329.00 XCSE
GENMAB A/S 26-Mar-25 10:03:45 AM 28 1329.00 XCSE
GENMAB A/S 26-Mar-25 10:03:45 AM 24 1328.50 CEUX
GENMAB A/S 26-Mar-25 10:03:45 AM 50 1328.50 CEUX
GENMAB A/S 26-Mar-25 10:04:21 AM 66 1328.50 CEUX
GENMAB A/S 26-Mar-25 10:04:46 AM 71 1328.00 XCSE
GENMAB A/S 26-Mar-25 10:04:50 AM 23 1328.00 XCSE
GENMAB A/S 26-Mar-25 10:04:50 AM 42 1328.00 XCSE
GENMAB A/S 26-Mar-25 10:04:50 AM 4 1328.00 XCSE
GENMAB A/S 26-Mar-25 10:04:50 AM 25 1328.00 XCSE
GENMAB A/S 26-Mar-25 10:05:29 AM 70 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:29 AM 21 1330.00 CEUX
GENMAB A/S 26-Mar-25 10:05:29 AM 18 1330.00 AQEU
GENMAB A/S 26-Mar-25 10:05:30 AM 58 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 39 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 11 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 12 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 42 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 1 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 12 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 13 1330.00 XCSE
GENMAB A/S 26-Mar-25 10:05:30 AM 51 1330.00 CEUX
GENMAB A/S 26-Mar-25 10:05:30 AM 25 1330.00 TQEX
GENMAB A/S 26-Mar-25 10:05:30 AM 7 1330.00 AQEU
GENMAB A/S 26-Mar-25 10:05:53 AM 75 1329.00 XCSE
GENMAB A/S 26-Mar-25 10:05:53 AM 74 1329.00 CEUX
GENMAB A/S 26-Mar-25 10:05:53 AM 23 1329.00 AQEU
GENMAB A/S 26-Mar-25 10:11:06 AM 13 1331.50 XCSE
GENMAB A/S 26-Mar-25 10:11:12 AM 25 1331.50 XCSE
GENMAB A/S 26-Mar-25 10:11:57 AM 13 1331.50 XCSE
GENMAB A/S 26-Mar-25 10:11:57 AM 10 1331.50 XCSE
GENMAB A/S 26-Mar-25 10:11:57 AM 37 1331.50 XCSE

5

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:11:57 AM 42 1331.50 XCSE
GENMAB A/S 26-Mar-25 10:12:51 AM 73 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:12:56 AM 15 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:12:56 AM 12 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:12:56 AM 19 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:12:56 AM 69 1333.00 CEUX
GENMAB A/S 26-Mar-25 10:13:21 AM 5 1333.50 CEUX
GENMAB A/S 26-Mar-25 10:13:21 AM 68 1333.50 CEUX
GENMAB A/S 26-Mar-25 10:13:22 AM 10 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:13:22 AM 7 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:14:23 AM 27 1334.00 TQEX
GENMAB A/S 26-Mar-25 10:14:23 AM 1 1334.00 TQEX
GENMAB A/S 26-Mar-25 10:14:26 AM 3 1334.00 XCSE
GENMAB A/S 26-Mar-25 10:14:32 AM 6 1333.50 XCSE
GENMAB A/S 26-Mar-25 10:16:02 AM 10 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:02 AM 42 1334.00 XCSE
GENMAB A/S 26-Mar-25 10:16:02 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:02 AM 75 1334.50 CEUX
GENMAB A/S 26-Mar-25 10:16:02 AM 23 1334.00 TQEX
GENMAB A/S 26-Mar-25 10:16:02 AM 39 1334.00 AQEU
GENMAB A/S 26-Mar-25 10:16:03 AM 30 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:03 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:09 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:09 AM 30 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:09 AM 70 1334.50 CEUX
GENMAB A/S 26-Mar-25 10:16:27 AM 30 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:27 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:27 AM 58 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:27 AM 6 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:47 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:47 AM 10 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:16:48 AM 27 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:17:03 AM 37 1334.00 AQEU
GENMAB A/S 26-Mar-25 10:17:29 AM 11 1335.00 TQEX
GENMAB A/S 26-Mar-25 10:17:44 AM 16 1335.00 TQEX
GENMAB A/S 26-Mar-25 10:18:06 AM 73 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:18:06 AM 72 1334.50 CEUX
GENMAB A/S 26-Mar-25 10:18:06 AM 23 1334.50 AQEU
GENMAB A/S 26-Mar-25 10:18:55 AM 23 1334.00 XCSE
GENMAB A/S 26-Mar-25 10:20:26 AM 42 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:20:26 AM 1 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:20:26 AM 2 1334.50 XCSE
GENMAB A/S 26-Mar-25 10:21:14 AM 25 1336.00 CEUX
GENMAB A/S 26-Mar-25 10:22:04 AM 73 1336.00 XCSE
GENMAB A/S 26-Mar-25 10:22:04 AM 48 1336.00 CEUX

6

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:22:04 AM 23 1336.00 TQEX
GENMAB A/S 26-Mar-25 10:22:04 AM 23 1336.00 AQEU
GENMAB A/S 26-Mar-25 10:22:54 AM 42 1336.00 XCSE
GENMAB A/S 26-Mar-25 10:22:54 AM 11 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:54 AM 41 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:55 AM 12 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:55 AM 1 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:55 AM 58 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:55 AM 12 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:55 AM 11 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:22:57 AM 73 1337.00 XCSE
GENMAB A/S 26-Mar-25 10:22:57 AM 20 1337.00 XCSE
GENMAB A/S 26-Mar-25 10:22:57 AM 35 1337.00 XCSE
GENMAB A/S 26-Mar-25 10:22:59 AM 24 1337.00 AQEU
GENMAB A/S 26-Mar-25 10:23:06 AM 60 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:23:06 AM 15 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:23:06 AM 25 1336.50 CEUX
GENMAB A/S 26-Mar-25 10:23:06 AM 47 1336.50 CEUX
GENMAB A/S 26-Mar-25 10:23:06 AM 9 1336.50 TQEX
GENMAB A/S 26-Mar-25 10:23:06 AM 33 1336.50 TQEX
GENMAB A/S 26-Mar-25 10:23:57 AM 69 1336.50 CEUX
GENMAB A/S 26-Mar-25 10:25:08 AM 11 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:25:08 AM 10 1336.50 XCSE
GENMAB A/S 26-Mar-25 10:25:21 AM 71 1336.00 XCSE
GENMAB A/S 26-Mar-25 10:25:21 AM 69 1335.50 CEUX
GENMAB A/S 26-Mar-25 10:25:21 AM 27 1336.00 AQEU
GENMAB A/S 26-Mar-25 10:25:23 AM 1 1336.00 AQEU
GENMAB A/S 26-Mar-25 10:25:28 AM 73 1335.00 XCSE
GENMAB A/S 26-Mar-25 10:25:28 AM 1 1336.00 AQEU
GENMAB A/S 26-Mar-25 10:26:45 AM 23 1337.00 AQEU
GENMAB A/S 26-Mar-25 10:27:10 AM 10 1337.50 XCSE
GENMAB A/S 26-Mar-25 10:27:10 AM 42 1337.50 XCSE
GENMAB A/S 26-Mar-25 10:27:10 AM 12 1337.50 XCSE
GENMAB A/S 26-Mar-25 10:27:46 AM 74 1338.50 CEUX
GENMAB A/S 26-Mar-25 10:29:07 AM 10 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:29:07 AM 30 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:29:07 AM 27 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:29:07 AM 3 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:29:07 AM 23 1338.50 AQEU
GENMAB A/S 26-Mar-25 10:30:35 AM 69 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:30:35 AM 44 1339.50 CEUX
GENMAB A/S 26-Mar-25 10:30:35 AM 28 1339.50 CEUX
GENMAB A/S 26-Mar-25 10:31:01 AM 4 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:01 AM 30 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:01 AM 72 1338.50 XCSE

7

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:31:01 AM 18 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:01 AM 42 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:01 AM 58 1338.50 CEUX
GENMAB A/S 26-Mar-25 10:31:01 AM 41 1338.50 TQEX
GENMAB A/S 26-Mar-25 10:31:01 AM 32 1339.00 AQEU
GENMAB A/S 26-Mar-25 10:31:06 AM 18 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:06 AM 10 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:06 AM 35 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:31:26 AM 2 1338.50 XCSE
GENMAB A/S 26-Mar-25 10:32:32 AM 73 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:32:32 AM 30 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:32:32 AM 19 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:32:32 AM 1 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:32:32 AM 29 1339.50 CEUX
GENMAB A/S 26-Mar-25 10:32:32 AM 18 1339.50 CEUX
GENMAB A/S 26-Mar-25 10:32:32 AM 3 1339.50 CEUX
GENMAB A/S 26-Mar-25 10:33:11 AM 12 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:33:11 AM 2 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:33:23 AM 25 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:34:20 AM 71 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:34:20 AM 38 1340.00 CEUX
GENMAB A/S 26-Mar-25 10:34:20 AM 20 1340.00 CEUX
GENMAB A/S 26-Mar-25 10:35:03 AM 1 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:35:03 AM 1 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:36:14 AM 11 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:36:14 AM 26 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:36:14 AM 36 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:36:14 AM 3 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:36:14 AM 11 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:37:11 AM 70 1340.00 XCSE
GENMAB A/S 26-Mar-25 10:37:11 AM 69 1340.00 CEUX
GENMAB A/S 26-Mar-25 10:38:01 AM 37 1339.50 AQEU
GENMAB A/S 26-Mar-25 10:38:01 AM 1 1339.50 AQEU
GENMAB A/S 26-Mar-25 10:38:21 AM 74 1339.50 XCSE
GENMAB A/S 26-Mar-25 10:41:26 AM 2 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:42:17 AM 71 1340.50 XCSE
GENMAB A/S 26-Mar-25 10:42:52 AM 71 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:43:04 AM 10 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:04 AM 69 1341.50 CEUX
GENMAB A/S 26-Mar-25 10:43:04 AM 23 1341.50 TQEX
GENMAB A/S 26-Mar-25 10:43:04 AM 26 1341.50 AQEU
GENMAB A/S 26-Mar-25 10:43:11 AM 39 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 25 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 25 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 45 1341.00 XCSE

8

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:43:11 AM 3 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 42 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 10 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 42 1341.00 XCSE
GENMAB A/S 26-Mar-25 10:43:11 AM 71 1340.50 CEUX
GENMAB A/S 26-Mar-25 10:43:11 AM 31 1340.50 TQEX
GENMAB A/S 26-Mar-25 10:43:11 AM 24 1340.50 AQEU
GENMAB A/S 26-Mar-25 10:43:59 AM 37 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 23 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 42 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 26 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 12 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 11 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:43:59 AM 8 1341.50 XCSE
GENMAB A/S 26-Mar-25 10:44:50 AM 75 1342.00 CEUX
GENMAB A/S 26-Mar-25 10:45:28 AM 25 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 19 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 11 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 11 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 23 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:31 AM 11 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:41 AM 13 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:41 AM 22 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:45:56 AM 35 1343.50 XCSE
GENMAB A/S 26-Mar-25 10:45:56 AM 26 1343.50 XCSE
GENMAB A/S 26-Mar-25 10:46:22 AM 71 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:46:22 AM 71 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:46:22 AM 32 1343.00 TQEX
GENMAB A/S 26-Mar-25 10:46:22 AM 24 1343.00 AQEU
GENMAB A/S 26-Mar-25 10:46:23 AM 71 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:46:23 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:49:43 AM 26 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:49:43 AM 25 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:49:43 AM 36 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:16 AM 72 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:16 AM 32 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:51:16 AM 71 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:51:16 AM 25 1343.00 TQEX
GENMAB A/S 26-Mar-25 10:51:16 AM 27 1343.00 AQEU
GENMAB A/S 26-Mar-25 10:51:44 AM 23 1342.50 TQEX
GENMAB A/S 26-Mar-25 10:51:47 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:47 AM 36 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:47 AM 14 1343.00 XCSE

9

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 10:51:47 AM 19 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:47 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:47 AM 2 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:47 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:55 AM 3 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:55 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:55 AM 42 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:55 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:51:55 AM 27 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:52:24 AM 44 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:52:24 AM 21 1342.00 CEUX
GENMAB A/S 26-Mar-25 10:52:24 AM 49 1342.00 CEUX
GENMAB A/S 26-Mar-25 10:52:24 AM 25 1342.00 AQEU
GENMAB A/S 26-Mar-25 10:54:10 AM 2 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:10 AM 27 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:10 AM 42 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:10 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:10 AM 4 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:10 AM 9 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:45 AM 19 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:45 AM 17 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:45 AM 2 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:45 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:45 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:54:56 AM 72 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:55:58 AM 4 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:55:58 AM 1 1343.00 TQEX
GENMAB A/S 26-Mar-25 10:56:02 AM 23 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:56:02 AM 14 1343.00 XCSE
GENMAB A/S 26-Mar-25 10:56:02 AM 37 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:56:02 AM 34 1343.00 CEUX
GENMAB A/S 26-Mar-25 10:56:02 AM 22 1343.00 TQEX
GENMAB A/S 26-Mar-25 10:57:00 AM 23 1342.50 AQEU
GENMAB A/S 26-Mar-25 10:57:25 AM 2 1342.50 XCSE
GENMAB A/S 26-Mar-25 10:58:13 AM 72 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:58:13 AM 25 1342.00 CEUX
GENMAB A/S 26-Mar-25 10:58:13 AM 49 1342.00 CEUX
GENMAB A/S 26-Mar-25 10:58:43 AM 12 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:58:43 AM 23 1342.00 XCSE
GENMAB A/S 26-Mar-25 10:59:26 AM 28 1342.00 XCSE
GENMAB A/S 26-Mar-25 11:00:01 AM 19 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:01 AM 23 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:01 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:01 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:01 AM 42 1343.00 XCSE

10

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:00:01 AM 33 1342.50 TQEX
GENMAB A/S 26-Mar-25 11:00:02 AM 15 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:02 AM 11 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:02 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:02 AM 13 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:02 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:02 AM 42 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:26 AM 1 1342.50 CEUX
GENMAB A/S 26-Mar-25 11:00:45 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 13 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 65 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 4 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:00:45 AM 75 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:02:26 AM 11 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:02:27 AM 47 1342.00 XCSE
GENMAB A/S 26-Mar-25 11:02:27 AM 7 1342.00 XCSE
GENMAB A/S 26-Mar-25 11:02:27 AM 3 1342.00 CEUX
GENMAB A/S 26-Mar-25 11:03:26 AM 12 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:03:26 AM 2 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:03:26 AM 25 1342.50 CEUX
GENMAB A/S 26-Mar-25 11:03:27 AM 1 1342.50 CEUX
GENMAB A/S 26-Mar-25 11:03:35 AM 23 1342.50 TQEX
GENMAB A/S 26-Mar-25 11:03:35 AM 3 1342.50 TQEX
GENMAB A/S 26-Mar-25 11:03:39 AM 15 1342.00 XCSE
GENMAB A/S 26-Mar-25 11:03:39 AM 4 1342.00 CEUX
GENMAB A/S 26-Mar-25 11:03:40 AM 10 1342.00 CEUX
GENMAB A/S 26-Mar-25 11:04:26 AM 1 1342.50 CEUX
GENMAB A/S 26-Mar-25 11:04:52 AM 75 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:04:59 AM 28 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:04:59 AM 40 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:04:59 AM 12 1342.50 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 1 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 18 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 12 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 2 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 10 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:40 AM 18 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:05:41 AM 38 1343.00 XCSE
GENMAB A/S 26-Mar-25 11:05:41 AM 21 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:05:44 AM 11 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:05:50 AM 36 1343.00 CEUX

11

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:06:04 AM 21 1343.00 CEUX
GENMAB A/S 26-Mar-25 11:06:37 AM 2 1344.50 XCSE
GENMAB A/S 26-Mar-25 11:06:42 AM 3 1344.50 TQEX
GENMAB A/S 26-Mar-25 11:06:42 AM 7 1344.50 TQEX
GENMAB A/S 26-Mar-25 11:06:42 AM 34 1344.50 TQEX
GENMAB A/S 26-Mar-25 11:08:26 AM 4 1345.00 CEUX
GENMAB A/S 26-Mar-25 11:08:44 AM 14 1346.50 AQEU
GENMAB A/S 26-Mar-25 11:08:48 AM 1 1346.50 AQEU
GENMAB A/S 26-Mar-25 11:08:48 AM 1 1346.50 AQEU
GENMAB A/S 26-Mar-25 11:08:51 AM 13 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:08:51 AM 35 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:08:51 AM 35 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:08:51 AM 59 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:09:12 AM 26 1346.50 AQEU
GENMAB A/S 26-Mar-25 11:09:25 AM 2 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:09:25 AM 1 1346.50 CEUX
GENMAB A/S 26-Mar-25 11:09:26 AM 2 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:09:26 AM 15 1346.50 CEUX
GENMAB A/S 26-Mar-25 11:10:25 AM 5 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:10:25 AM 11 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:10:25 AM 5 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:10:25 AM 23 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:10:37 AM 4 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:10:37 AM 5 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:11:03 AM 1 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:11:20 AM 22 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:11:20 AM 25 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:11:20 AM 2 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:12:55 AM 53 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:55 AM 41 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:56 AM 78 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:56 AM 10 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:56 AM 16 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:57 AM 9 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:58 AM 12 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:12:58 AM 26 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:12:58 AM 26 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:12:58 AM 36 1347.50 CEUX
GENMAB A/S 26-Mar-25 11:12:58 AM 23 1347.50 AQEU
GENMAB A/S 26-Mar-25 11:12:59 AM 24 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:12:59 AM 12 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:12:59 AM 10 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:12:59 AM 22 1347.50 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 32 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 10 1347.50 XCSE

12

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:13:05 AM 10 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 31 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 11 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 32 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 42 1347.00 XCSE
GENMAB A/S 26-Mar-25 11:13:05 AM 5 1347.50 CEUX
GENMAB A/S 26-Mar-25 11:13:05 AM 36 1347.50 CEUX
GENMAB A/S 26-Mar-25 11:13:05 AM 4 1347.50 CEUX
GENMAB A/S 26-Mar-25 11:13:05 AM 7 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:13:05 AM 62 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:13:05 AM 37 1347.00 TQEX
GENMAB A/S 26-Mar-25 11:13:05 AM 2 1347.00 TQEX
GENMAB A/S 26-Mar-25 11:13:07 AM 4 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:13:07 AM 11 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:13:07 AM 4 1347.00 CEUX
GENMAB A/S 26-Mar-25 11:14:23 AM 26 1346.50 CEUX
GENMAB A/S 26-Mar-25 11:14:23 AM 39 1346.50 CEUX
GENMAB A/S 26-Mar-25 11:14:45 AM 12 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:14:45 AM 2 1346.50 XCSE
GENMAB A/S 26-Mar-25 11:16:26 AM 1 1346.50 CEUX
GENMAB A/S 26-Mar-25 11:18:27 AM 71 1348.00 XCSE
GENMAB A/S 26-Mar-25 11:18:27 AM 42 1348.50 XCSE
GENMAB A/S 26-Mar-25 11:18:27 AM 12 1348.50 XCSE
GENMAB A/S 26-Mar-25 11:18:27 AM 7 1348.50 XCSE
GENMAB A/S 26-Mar-25 11:18:27 AM 10 1348.50 XCSE
GENMAB A/S 26-Mar-25 11:18:27 AM 5 1348.50 CEUX
GENMAB A/S 26-Mar-25 11:18:27 AM 12 1348.00 CEUX
GENMAB A/S 26-Mar-25 11:18:27 AM 4 1348.50 CEUX
GENMAB A/S 26-Mar-25 11:18:27 AM 63 1348.00 CEUX
GENMAB A/S 26-Mar-25 11:18:38 AM 4 1349.00 XCSE
GENMAB A/S 26-Mar-25 11:19:00 AM 61 1348.50 XCSE
GENMAB A/S 26-Mar-25 11:19:54 AM 10 1349.50 CEUX
GENMAB A/S 26-Mar-25 11:19:54 AM 64 1349.50 CEUX
GENMAB A/S 26-Mar-25 11:19:54 AM 2 1349.50 CEUX
GENMAB A/S 26-Mar-25 11:19:54 AM 1 1349.50 CEUX
GENMAB A/S 26-Mar-25 11:19:54 AM 17 1349.50 CEUX
GENMAB A/S 26-Mar-25 11:19:58 AM 13 1350.50 CEUX
GENMAB A/S 26-Mar-25 11:19:58 AM 8 1350.50 CEUX
GENMAB A/S 26-Mar-25 11:20:01 AM 71 1350.50 XCSE
GENMAB A/S 26-Mar-25 11:21:30 AM 42 1351.00 XCSE
GENMAB A/S 26-Mar-25 11:21:30 AM 23 1351.00 CEUX
GENMAB A/S 26-Mar-25 11:21:30 AM 8 1351.00 CEUX
GENMAB A/S 26-Mar-25 11:22:34 AM 9 1351.50 CEUX
GENMAB A/S 26-Mar-25 11:22:34 AM 16 1351.50 CEUX
GENMAB A/S 26-Mar-25 11:22:34 AM 30 1351.50 CEUX

13

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:22:34 AM 1 1351.50 CEUX
GENMAB A/S 26-Mar-25 11:23:36 AM 35 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:36 AM 42 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:36 AM 8 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:36 AM 9 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 11 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 10 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 15 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 2 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 42 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 10 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:37 AM 12 1352.00 CEUX
GENMAB A/S 26-Mar-25 11:23:38 AM 17 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:38 AM 14 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:39 AM 12 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:39 AM 16 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:40 AM 9 1352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:40 AM 16 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:40 AM 17 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:41 AM 10 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:41 AM 11 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:42 AM 15 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:42 AM 7 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:23:42 AM 24 1,352.00 TQEX
GENMAB A/S 26-Mar-25 11:24:25 AM 36 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:24:26 AM 13 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:24:26 AM 1 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:24:26 AM 1 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:24:41 AM 36 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:25:00 AM 32 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:25:53 AM 11 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:25:53 AM 43 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:25:53 AM 1 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:25:53 AM 27 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:25:54 AM 71 1,351.00 XCSE
GENMAB A/S 26-Mar-25 11:26:00 AM 20 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:00 AM 17 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:25 AM 42 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:25 AM 10 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:26 AM 2 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:31 AM 11 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:26:38 AM 15 1,352.50 XCSE
GENMAB A/S 26-Mar-25 11:26:38 AM 35 1,352.50 XCSE
GENMAB A/S 26-Mar-25 11:26:38 AM 27 1,352.50 XCSE
GENMAB A/S 26-Mar-25 11:26:38 AM 2 1,352.50 XCSE

14

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:26:46 AM 36 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:26:47 AM 5 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:26:54 AM 5 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:26:54 AM 5 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:26:54 AM 12 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:27:15 AM 23 1,352.00 XCSE
GENMAB A/S 26-Mar-25 11:27:27 AM 70 1,351.00 XCSE
GENMAB A/S 26-Mar-25 11:27:27 AM 74 1,349.50 XCSE
GENMAB A/S 26-Mar-25 11:27:27 AM 70 1,351.00 CEUX
GENMAB A/S 26-Mar-25 11:27:27 AM 29 1,351.00 TQEX
GENMAB A/S 26-Mar-25 11:27:27 AM 24 1,351.00 AQEU
GENMAB A/S 26-Mar-25 11:27:31 AM 23 1,351.00 TQEX
GENMAB A/S 26-Mar-25 11:28:25 AM 72 1,350.50 XCSE
GENMAB A/S 26-Mar-25 11:28:40 AM 9 1,348.50 XCSE
GENMAB A/S 26-Mar-25 11:28:40 AM 69 1,349.50 XCSE
GENMAB A/S 26-Mar-25 11:28:40 AM 69 1,350.00 CEUX
GENMAB A/S 26-Mar-25 11:28:40 AM 28 1,350.00 TQEX
GENMAB A/S 26-Mar-25 11:28:40 AM 23 1,350.00 AQEU
GENMAB A/S 26-Mar-25 11:29:11 AM 67 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:29:11 AM 67 1,349.00 XCSE
GENMAB A/S 26-Mar-25 11:29:11 AM 1 1,348.50 CEUX
GENMAB A/S 26-Mar-25 11:29:11 AM 71 1,348.50 CEUX
GENMAB A/S 26-Mar-25 11:29:15 AM 74 1,347.50 CEUX
GENMAB A/S 26-Mar-25 11:29:15 AM 26 1,348.00 AQEU
GENMAB A/S 26-Mar-25 11:29:56 AM 75 1,347.00 XCSE
GENMAB A/S 26-Mar-25 11:30:36 AM 49 1,348.00 CEUX
GENMAB A/S 26-Mar-25 11:32:07 AM 22 1,348.00 CEUX
GENMAB A/S 26-Mar-25 11:34:05 AM 3 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:05 AM 37 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:05 AM 4 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:35 AM 1 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:35 AM 12 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:45 AM 12 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:34:55 AM 12 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:37:25 AM 53 1,348.50 XCSE
GENMAB A/S 26-Mar-25 11:37:25 AM 18 1,348.50 XCSE
GENMAB A/S 26-Mar-25 11:37:25 AM 2 1,348.00 XCSE
GENMAB A/S 26-Mar-25 11:37:25 AM 18 1,348.50 CEUX
GENMAB A/S 26-Mar-25 11:37:25 AM 22 1,348.50 CEUX
GENMAB A/S 26-Mar-25 11:37:25 AM 34 1,348.50 CEUX
GENMAB A/S 26-Mar-25 11:39:05 AM 17 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:39:05 AM 40 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:39:05 AM 37 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:39:19 AM 1 1,351.00 CEUX
GENMAB A/S 26-Mar-25 11:39:19 AM 10 1,351.00 CEUX

15

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:39:19 AM 58 1,351.00 CEUX
GENMAB A/S 26-Mar-25 11:39:24 AM 46 1,351.00 XCSE
GENMAB A/S 26-Mar-25 11:39:34 AM 7 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:39:35 AM 10 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:39:35 AM 18 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:40:41 AM 12 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:40:41 AM 3 1,351.50 XCSE
GENMAB A/S 26-Mar-25 11:42:25 AM 33 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:42:25 AM 16 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:42:25 AM 1 1,352.00 CEUX
GENMAB A/S 26-Mar-25 11:42:45 AM 59 1,354.50 XCSE
GENMAB A/S 26-Mar-25 11:42:45 AM 35 1,354.50 XCSE
GENMAB A/S 26-Mar-25 11:42:46 AM 47 1,354.50 XCSE
GENMAB A/S 26-Mar-25 11:43:10 AM 13 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:43:45 AM 5 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:43:45 AM 13 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:43:45 AM 5 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:44:14 AM 69 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:14 AM 25 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:14 AM 1 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:44:15 AM 48 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:15 AM 16 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:15 AM 78 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:15 AM 21 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:15 AM 25 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:15 AM 4 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:44:15 AM 4 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:44:15 AM 2 1,355.50 CEUX
GENMAB A/S 26-Mar-25 11:44:15 AM 43 1,355.00 TQEX
GENMAB A/S 26-Mar-25 11:44:16 AM 23 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:34 AM 23 1,355.00 CEUX
GENMAB A/S 26-Mar-25 11:44:35 AM 21 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:35 AM 2 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:55 AM 7 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:44:55 AM 25 1,355.00 XCSE
GENMAB A/S 26-Mar-25 11:45:13 AM 59 1,354.50 XCSE
GENMAB A/S 26-Mar-25 11:45:13 AM 13 1,354.50 XCSE
GENMAB A/S 26-Mar-25 11:45:13 AM 17 1,354.50 CEUX
GENMAB A/S 26-Mar-25 11:45:13 AM 56 1,354.50 CEUX
GENMAB A/S 26-Mar-25 11:45:13 AM 30 1,354.00 TQEX
GENMAB A/S 26-Mar-25 11:45:13 AM 32 1,354.50 AQEU
GENMAB A/S 26-Mar-25 11:45:19 AM 23 1,353.50 XCSE
GENMAB A/S 26-Mar-25 11:45:22 AM 51 1,353.50 XCSE
GENMAB A/S 26-Mar-25 11:45:22 AM 74 1,353.50 CEUX
GENMAB A/S 26-Mar-25 11:45:22 AM 4 1,354.00 TQEX

16

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:45:22 AM 32 1,353.50 AQEU
GENMAB A/S 26-Mar-25 11:48:38 AM 7 1,354.00 XCSE
GENMAB A/S 26-Mar-25 11:49:43 AM 4 1,354.50 CEUX
GENMAB A/S 26-Mar-25 11:50:14 AM 32 1,354.50 CEUX
GENMAB A/S 26-Mar-25 11:51:29 AM 3 1,356.50 CEUX
GENMAB A/S 26-Mar-25 11:51:48 AM 2 1,357.00 XCSE
GENMAB A/S 26-Mar-25 11:51:48 AM 50 1,357.00 XCSE
GENMAB A/S 26-Mar-25 11:51:48 AM 29 1,357.00 XCSE
GENMAB A/S 26-Mar-25 11:51:48 AM 72 1,356.50 CEUX
GENMAB A/S 26-Mar-25 11:51:48 AM 26 1,356.50 TQEX
GENMAB A/S 26-Mar-25 11:51:51 AM 70 1,357.00 CEUX
GENMAB A/S 26-Mar-25 11:51:51 AM 29 1,357.00 TQEX
GENMAB A/S 26-Mar-25 11:52:05 AM 15 1,357.50 XCSE
GENMAB A/S 26-Mar-25 11:52:05 AM 7 1,357.50 XCSE
GENMAB A/S 26-Mar-25 11:53:44 AM 75 1,359.00 CEUX
GENMAB A/S 26-Mar-25 11:53:45 AM 29 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:53:50 AM 50 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:53:53 AM 50 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:53:58 AM 54 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:53:58 AM 18 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:53:58 AM 23 1,359.50 TQEX
GENMAB A/S 26-Mar-25 11:54:04 AM 11 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:04 AM 10 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:04 AM 42 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:04 AM 10 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:07 AM 50 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:17 AM 70 1,361.00 CEUX
GENMAB A/S 26-Mar-25 11:54:21 AM 62 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:25 AM 37 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:55 AM 7 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:54:55 AM 2 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:55:25 AM 1 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:55:25 AM 24 1,361.00 XCSE
GENMAB A/S 26-Mar-25 11:55:43 AM 24 1,361.50 XCSE
GENMAB A/S 26-Mar-25 11:55:43 AM 18 1,361.50 XCSE
GENMAB A/S 26-Mar-25 11:55:43 AM 23 1,361.50 XCSE
GENMAB A/S 26-Mar-25 11:55:43 AM 21 1,361.50 XCSE
GENMAB A/S 26-Mar-25 11:55:58 AM 70 1,360.50 XCSE
GENMAB A/S 26-Mar-25 11:55:58 AM 1 1,360.50 XCSE
GENMAB A/S 26-Mar-25 11:55:58 AM 55 1,360.50 AQEU
GENMAB A/S 26-Mar-25 11:57:30 AM 75 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:57:30 AM 69 1,360.00 CEUX
GENMAB A/S 26-Mar-25 11:57:30 AM 23 1,360.50 TQEX
GENMAB A/S 26-Mar-25 11:57:30 AM 50 1,359.50 AQEU
GENMAB A/S 26-Mar-25 11:57:30 AM 56 1,360.50 AQEU

17

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 11:59:25 AM 11 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:59:25 AM 10 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:59:26 AM 1 1,359.50 XCSE
GENMAB A/S 26-Mar-25 11:59:35 AM 18 1,360.00 XCSE
GENMAB A/S 26-Mar-25 11:59:35 AM 22 1,360.00 XCSE
GENMAB A/S 26-Mar-25 11:59:35 AM 10 1,360.00 XCSE
GENMAB A/S 26-Mar-25 11:59:35 AM 10 1,360.00 XCSE
GENMAB A/S 26-Mar-25 12:01:26 PM 1 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:02:02 PM 12 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:02:26 PM 2 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:02:26 PM 1 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:03:26 PM 1 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:03:26 PM 2 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:03:27 PM 4 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:03:27 PM 2 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:03:45 PM 42 1,362.50 TQEX
GENMAB A/S 26-Mar-25 12:03:58 PM 10 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:03:58 PM 12 1,362.50 CEUX
GENMAB A/S 26-Mar-25 12:03:58 PM 4 1,362.50 CEUX
GENMAB A/S 26-Mar-25 12:04:26 PM 1 1,362.50 CEUX
GENMAB A/S 26-Mar-25 12:04:27 PM 11 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:04:27 PM 10 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:04:27 PM 31 1,362.50 CEUX
GENMAB A/S 26-Mar-25 12:05:25 PM 1 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:05:25 PM 1 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:05:25 PM 1 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:05:25 PM 1 1,362.50 CEUX
GENMAB A/S 26-Mar-25 12:05:26 PM 4 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:06:25 PM 1 1,362.50 XCSE
GENMAB A/S 26-Mar-25 12:06:34 PM 1 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:06:34 PM 18 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:06:40 PM 12 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:06:40 PM 22 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:06:40 PM 36 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:06:40 PM 24 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:06:40 PM 26 1,362.50 TQEX
GENMAB A/S 26-Mar-25 12:07:09 PM 12 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:09 PM 35 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:09 PM 17 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:09 PM 30 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:09 PM 5 1,363.00 CEUX
GENMAB A/S 26-Mar-25 12:07:10 PM 34 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:10 PM 39 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:10 PM 12 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:10 PM 11 1,363.00 XCSE

18

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 12:07:10 PM 10 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:10 PM 10 1,363.00 XCSE
GENMAB A/S 26-Mar-25 12:07:18 PM 70 1,364.00 CEUX
GENMAB A/S 26-Mar-25 12:07:19 PM 30 1,364.50 XCSE
GENMAB A/S 26-Mar-25 12:07:19 PM 71 1,364.50 CEUX
GENMAB A/S 26-Mar-25 12:07:21 PM 70 1,364.00 CEUX
GENMAB A/S 26-Mar-25 12:08:52 PM 71 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:08:52 PM 69 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:08:52 PM 73 1,370.00 AQEU
GENMAB A/S 26-Mar-25 12:08:53 PM 33 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:08:53 PM 50 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:08:54 PM 18 1,370.50 XCSE
GENMAB A/S 26-Mar-25 12:08:54 PM 1 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:09:01 PM 69 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:09:01 PM 72 1,371.00 CEUX
GENMAB A/S 26-Mar-25 12:09:01 PM 74 1,370.50 AQEU
GENMAB A/S 26-Mar-25 12:09:02 PM 75 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:09:02 PM 74 1,370.00 CEUX
GENMAB A/S 26-Mar-25 12:09:04 PM 13 1,369.00 XCSE
GENMAB A/S 26-Mar-25 12:09:04 PM 69 1,369.50 AQEU
GENMAB A/S 26-Mar-25 12:09:06 PM 60 1,369.00 XCSE
GENMAB A/S 26-Mar-25 12:09:06 PM 74 1,369.00 CEUX
GENMAB A/S 26-Mar-25 12:09:06 PM 1 1,369.00 CEUX
GENMAB A/S 26-Mar-25 12:13:05 PM 10 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:13:49 PM 11 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:13:52 PM 11 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:13:52 PM 11 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:13:52 PM 28 1,371.50 AQEU
GENMAB A/S 26-Mar-25 12:13:59 PM 17 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:14:07 PM 74 1,372.00 XCSE
GENMAB A/S 26-Mar-25 12:14:07 PM 62 1,372.00 CEUX
GENMAB A/S 26-Mar-25 12:14:07 PM 23 1,372.00 TQEX
GENMAB A/S 26-Mar-25 12:14:27 PM 70 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:14:27 PM 24 1,370.50 CEUX
GENMAB A/S 26-Mar-25 12:14:27 PM 45 1,370.50 AQEU
GENMAB A/S 26-Mar-25 12:14:27 PM 17 1,371.50 AQEU
GENMAB A/S 26-Mar-25 12:15:25 PM 69 1,369.50 XCSE
GENMAB A/S 26-Mar-25 12:15:25 PM 28 1,369.50 CEUX
GENMAB A/S 26-Mar-25 12:17:25 PM 3 1,371.50 XCSE
GENMAB A/S 26-Mar-25 12:17:25 PM 2 1,371.50 XCSE
GENMAB A/S 26-Mar-25 12:17:25 PM 2 1,371.50 XCSE
GENMAB A/S 26-Mar-25 12:17:26 PM 38 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:17:26 PM 37 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:17:26 PM 39 1,371.00 CEUX
GENMAB A/S 26-Mar-25 12:17:26 PM 25 1,370.50 AQEU

19

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 12:18:04 PM 14 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:18:04 PM 59 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:18:04 PM 20 1,370.00 CEUX
GENMAB A/S 26-Mar-25 12:18:04 PM 18 1,370.00 CEUX
GENMAB A/S 26-Mar-25 12:18:04 PM 41 1,369.50 AQEU
GENMAB A/S 26-Mar-25 12:18:07 PM 6 1,369.00 XCSE
GENMAB A/S 26-Mar-25 12:18:07 PM 68 1,369.00 XCSE
GENMAB A/S 26-Mar-25 12:18:11 PM 44 1,368.50 CEUX
GENMAB A/S 26-Mar-25 12:18:11 PM 26 1,368.50 TQEX
GENMAB A/S 26-Mar-25 12:21:00 PM 23 1,370.00 AQEU
GENMAB A/S 26-Mar-25 12:21:25 PM 2 1,369.50 XCSE
GENMAB A/S 26-Mar-25 12:21:25 PM 70 1,369.50 XCSE
GENMAB A/S 26-Mar-25 12:21:25 PM 14 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:21:25 PM 2 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:21:25 PM 7 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:21:25 PM 46 1,369.50 CEUX
GENMAB A/S 26-Mar-25 12:21:51 PM 1 1,368.50 XCSE
GENMAB A/S 26-Mar-25 12:21:51 PM 4 1,368.50 CEUX
GENMAB A/S 26-Mar-25 12:25:25 PM 23 1,369.00 TQEX
GENMAB A/S 26-Mar-25 12:25:26 PM 2 1,369.50 XCSE
GENMAB A/S 26-Mar-25 12:25:26 PM 1 1,369.50 XCSE
GENMAB A/S 26-Mar-25 12:27:26 PM 75 1,370.00 XCSE
GENMAB A/S 26-Mar-25 12:27:26 PM 23 1,370.00 AQEU
GENMAB A/S 26-Mar-25 12:28:07 PM 6 1,370.50 XCSE
GENMAB A/S 26-Mar-25 12:28:07 PM 11 1,370.50 XCSE
GENMAB A/S 26-Mar-25 12:28:26 PM 1 1,370.50 XCSE
GENMAB A/S 26-Mar-25 12:29:53 PM 3 1,370.00 AQEU
GENMAB A/S 26-Mar-25 12:30:08 PM 1 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 30 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 30 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 1 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 11 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 27 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 10 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 2 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 43 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:08 PM 10 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 11 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 12 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 12 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 34 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 12 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 30 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:09 PM 30 1,371.00 XCSE
GENMAB A/S 26-Mar-25 12:30:22 PM 73 1,369.50 XCSE

20

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 12:30:22 PM 75 1,369.50 CEUX
GENMAB A/S 26-Mar-25 12:30:22 PM 41 1,369.50 TQEX
GENMAB A/S 26-Mar-25 12:30:45 PM 72 1,368.50 XCSE
GENMAB A/S 26-Mar-25 12:30:45 PM 38 1,368.50 CEUX
GENMAB A/S 26-Mar-25 12:30:47 PM 74 1,367.50 XCSE
GENMAB A/S 26-Mar-25 12:30:47 PM 40 1,367.50 CEUX
GENMAB A/S 26-Mar-25 12:30:55 PM 75 1,366.50 XCSE
GENMAB A/S 26-Mar-25 12:30:55 PM 73 1,366.50 CEUX
GENMAB A/S 26-Mar-25 12:30:57 PM 70 1,365.50 XCSE
GENMAB A/S 26-Mar-25 12:30:57 PM 75 1,365.50 CEUX
GENMAB A/S 26-Mar-25 12:31:29 PM 20 1,364.00 XCSE
GENMAB A/S 26-Mar-25 12:31:29 PM 35 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:31:29 PM 14 1,364.50 CEUX
GENMAB A/S 26-Mar-25 12:31:29 PM 35 1,364.50 CEUX
GENMAB A/S 26-Mar-25 12:36:45 PM 1 1,366.00 XCSE
GENMAB A/S 26-Mar-25 12:36:45 PM 11 1,366.00 XCSE
GENMAB A/S 26-Mar-25 12:36:45 PM 1 1,366.00 XCSE
GENMAB A/S 26-Mar-25 12:37:20 PM 23 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:37:20 PM 23 1,365.50 CEUX
GENMAB A/S 26-Mar-25 12:37:20 PM 40 1,365.00 TQEX
GENMAB A/S 26-Mar-25 12:37:20 PM 26 1,365.50 AQEU
GENMAB A/S 26-Mar-25 12:38:17 PM 24 1,365.00 AQEU
GENMAB A/S 26-Mar-25 12:38:37 PM 10 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:38:37 PM 30 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:38:37 PM 42 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:38:37 PM 12 1,365.00 XCSE
GENMAB A/S 26-Mar-25 12:38:37 PM 27 1,364.50 CEUX
GENMAB A/S 26-Mar-25 12:38:37 PM 14 1,364.50 CEUX
GENMAB A/S 26-Mar-25 12:39:10 PM 3 1,365.50 XCSE
GENMAB A/S 26-Mar-25 12:39:14 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 12:40:26 PM 63 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:40:26 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:40:35 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:40:35 PM 94 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:41:16 PM 74 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:41:21 PM 52 1364.00 XCSE
GENMAB A/S 26-Mar-25 12:41:21 PM 58 1364.00 CEUX
GENMAB A/S 26-Mar-25 12:41:21 PM 40 1364.00 TQEX
GENMAB A/S 26-Mar-25 12:41:21 PM 27 1364.00 AQEU
GENMAB A/S 26-Mar-25 12:43:51 PM 23 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:43:51 PM 75 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:43:51 PM 74 1365.00 CEUX
GENMAB A/S 26-Mar-25 12:45:47 PM 47 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:45:47 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:45:47 PM 1 1367.00 XCSE

21

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 12:45:47 PM 26 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:45:47 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 42 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 8 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 71 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 19 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 2 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 12:47:15 PM 69 1366.00 CEUX
GENMAB A/S 26-Mar-25 12:47:15 PM 42 1365.50 AQEU
GENMAB A/S 26-Mar-25 12:48:26 PM 74 1366.50 CEUX
GENMAB A/S 26-Mar-25 12:48:27 PM 20 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:48:27 PM 49 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:48:42 PM 6 1365.50 TQEX
GENMAB A/S 26-Mar-25 12:49:35 PM 73 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:52:26 PM 42 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:52:26 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:52:26 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:52:26 PM 19 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:53:23 PM 71 1366.00 CEUX
GENMAB A/S 26-Mar-25 12:53:26 PM 1 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 75 1365.50 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 21 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 42 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 37 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 13 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 42 1365.50 XCSE
GENMAB A/S 26-Mar-25 12:54:25 PM 67 1365.00 CEUX
GENMAB A/S 26-Mar-25 12:54:25 PM 30 1365.50 TQEX
GENMAB A/S 26-Mar-25 12:54:25 PM 41 1365.50 AQEU
GENMAB A/S 26-Mar-25 12:55:40 PM 44 1365.00 XCSE
GENMAB A/S 26-Mar-25 12:58:47 PM 23 1365.50 TQEX
GENMAB A/S 26-Mar-25 12:59:10 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:59:10 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:59:10 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 12:59:37 PM 71 1366.00 XCSE
GENMAB A/S 26-Mar-25 1:00:14 PM 4 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:00:14 PM 1 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:00:14 PM 42 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:00:14 PM 70 1366.00 CEUX
GENMAB A/S 26-Mar-25 1:00:14 PM 41 1366.50 TQEX
GENMAB A/S 26-Mar-25 1:01:14 PM 74 1368.00 XCSE

22

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 1:01:14 PM 73 1368.00 CEUX
GENMAB A/S 26-Mar-25 1:02:24 PM 42 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:02:26 PM 27 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:02:57 PM 69 1368.00 CEUX
GENMAB A/S 26-Mar-25 1:03:24 PM 21 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:03:24 PM 30 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:03:24 PM 15 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:03:24 PM 28 1367.50 AQEU
GENMAB A/S 26-Mar-25 1:03:26 PM 72 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:03:26 PM 1 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:03:26 PM 70 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:04:06 PM 6 1366.00 XCSE
GENMAB A/S 26-Mar-25 1:04:06 PM 69 1366.00 XCSE
GENMAB A/S 26-Mar-25 1:04:06 PM 72 1366.00 CEUX
GENMAB A/S 26-Mar-25 1:04:08 PM 71 1365.50 XCSE
GENMAB A/S 26-Mar-25 1:08:53 PM 25 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:08:53 PM 10 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:08:56 PM 72 1369.50 CEUX
GENMAB A/S 26-Mar-25 1:09:58 PM 34 1370.50 XCSE
GENMAB A/S 26-Mar-25 1:09:58 PM 42 1370.50 XCSE
GENMAB A/S 26-Mar-25 1:09:58 PM 18 1370.50 XCSE
GENMAB A/S 26-Mar-25 1:10:00 PM 75 1370.00 XCSE
GENMAB A/S 26-Mar-25 1:10:00 PM 36 1369.50 CEUX
GENMAB A/S 26-Mar-25 1:10:00 PM 23 1370.00 TQEX
GENMAB A/S 26-Mar-25 1:10:00 PM 25 1370.00 AQEU
GENMAB A/S 26-Mar-25 1:10:01 PM 75 1369.00 XCSE
GENMAB A/S 26-Mar-25 1:10:03 PM 9 1369.00 AQEU
GENMAB A/S 26-Mar-25 1:10:03 PM 18 1369.00 AQEU
GENMAB A/S 26-Mar-25 1:10:35 PM 35 1368.50 CEUX
GENMAB A/S 26-Mar-25 1:10:35 PM 34 1368.50 CEUX
GENMAB A/S 26-Mar-25 1:10:45 PM 74 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:11:14 PM 69 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:11:18 PM 66 1371.50 XCSE
GENMAB A/S 26-Mar-25 1:11:18 PM 48 1372.00 CEUX
GENMAB A/S 26-Mar-25 1:11:21 PM 23 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:12:10 PM 51 1373.50 XCSE
GENMAB A/S 26-Mar-25 1:12:10 PM 28 1373.00 CEUX
GENMAB A/S 26-Mar-25 1:12:24 PM 43 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:12:24 PM 29 1372.00 CEUX
GENMAB A/S 26-Mar-25 1:12:27 PM 50 1371.50 XCSE
GENMAB A/S 26-Mar-25 1:12:27 PM 44 1371.00 CEUX
GENMAB A/S 26-Mar-25 1:12:32 PM 25 1371.50 XCSE
GENMAB A/S 26-Mar-25 1:12:54 PM 41 1370.50 CEUX
GENMAB A/S 26-Mar-25 1:15:58 PM 5 1371.50 CEUX
GENMAB A/S 26-Mar-25 1:15:58 PM 18 1371.50 CEUX

23

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 1:16:13 PM 27 1372.50 TQEX
GENMAB A/S 26-Mar-25 1:19:25 PM 3 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:19:25 PM 4 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:19:48 PM 30 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:19:48 PM 17 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:20:25 PM 1 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:20:25 PM 1 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:20:25 PM 10 1372.50 XCSE
GENMAB A/S 26-Mar-25 1:20:42 PM 2 1373.50 XCSE
GENMAB A/S 26-Mar-25 1:20:42 PM 15 1373.50 XCSE
GENMAB A/S 26-Mar-25 1:21:06 PM 12 1373.50 XCSE
GENMAB A/S 26-Mar-25 1:21:06 PM 10 1373.50 XCSE
GENMAB A/S 26-Mar-25 1:21:55 PM 73 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:21:55 PM 42 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:21:55 PM 17 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:21:55 PM 35 1373.00 XCSE
GENMAB A/S 26-Mar-25 1:21:55 PM 61 1373.00 CEUX
GENMAB A/S 26-Mar-25 1:21:55 PM 28 1373.00 AQEU
GENMAB A/S 26-Mar-25 1:21:56 PM 69 1372.00 XCSE
GENMAB A/S 26-Mar-25 1:21:56 PM 20 1372.00 CEUX
GENMAB A/S 26-Mar-25 1:21:56 PM 3 1372.00 CEUX
GENMAB A/S 26-Mar-25 1:21:56 PM 23 1372.00 TQEX
GENMAB A/S 26-Mar-25 1:21:56 PM 26 1372.00 AQEU
GENMAB A/S 26-Mar-25 1:22:15 PM 70 1372.00 XCSE
GENMAB A/S 26-Mar-25 1:22:15 PM 26 1372.00 TQEX
GENMAB A/S 26-Mar-25 1:23:25 PM 49 1372.50 CEUX
GENMAB A/S 26-Mar-25 1:24:24 PM 71 1372.00 XCSE
GENMAB A/S 26-Mar-25 1:25:41 PM 23 1372.00 AQEU
GENMAB A/S 26-Mar-25 1:26:18 PM 73 1372.00 XCSE
GENMAB A/S 26-Mar-25 1:26:35 PM 9 1371.50 CEUX
GENMAB A/S 26-Mar-25 1:26:37 PM 38 1371.50 CEUX
GENMAB A/S 26-Mar-25 1:26:49 PM 60 1371.00 XCSE
GENMAB A/S 26-Mar-25 1:26:49 PM 43 1371.00 TQEX
GENMAB A/S 26-Mar-25 1:26:50 PM 75 1370.00 XCSE
GENMAB A/S 26-Mar-25 1:26:50 PM 24 1370.50 CEUX
GENMAB A/S 26-Mar-25 1:29:19 PM 9 1370.00 AQEU
GENMAB A/S 26-Mar-25 1:29:27 PM 8 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:29:31 PM 1 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:30:02 PM 5 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:30:02 PM 9 1369.50 XCSE
GENMAB A/S 26-Mar-25 1:30:25 PM 52 1369.00 CEUX
GENMAB A/S 26-Mar-25 1:30:27 PM 75 1368.50 XCSE
GENMAB A/S 26-Mar-25 1:30:30 PM 2 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:30:31 PM 10 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:30:59 PM 19 1367.50 CEUX

24

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 1:31:07 PM 27 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:31:15 PM 44 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:31:15 PM 27 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:32:30 PM 70 1366.00 XCSE
GENMAB A/S 26-Mar-25 1:32:30 PM 71 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:32:30 PM 46 1366.00 CEUX
GENMAB A/S 26-Mar-25 1:32:30 PM 24 1367.00 AQEU
GENMAB A/S 26-Mar-25 1:33:04 PM 75 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:33:04 PM 57 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:34:45 PM 75 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:34:45 PM 58 1366.50 CEUX
GENMAB A/S 26-Mar-25 1:35:38 PM 72 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:35:38 PM 23 1367.00 AQEU
GENMAB A/S 26-Mar-25 1:37:27 PM 23 1366.50 CEUX
GENMAB A/S 26-Mar-25 1:39:26 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:39:26 PM 71 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:39:26 PM 59 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:39:26 PM 24 1367.50 TQEX
GENMAB A/S 26-Mar-25 1:39:26 PM 24 1367.50 AQEU
GENMAB A/S 26-Mar-25 1:39:30 PM 70 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:40:21 PM 73 1365.50 XCSE
GENMAB A/S 26-Mar-25 1:40:21 PM 1 1365.50 CEUX
GENMAB A/S 26-Mar-25 1:40:21 PM 43 1365.50 CEUX
GENMAB A/S 26-Mar-25 1:40:31 PM 57 1365.50 CEUX
GENMAB A/S 26-Mar-25 1:41:00 PM 69 1365.00 XCSE
GENMAB A/S 26-Mar-25 1:41:00 PM 25 1365.00 TQEX
GENMAB A/S 26-Mar-25 1:41:08 PM 72 1364.00 XCSE
GENMAB A/S 26-Mar-25 1:41:08 PM 4 1364.00 CEUX
GENMAB A/S 26-Mar-25 1:41:08 PM 29 1364.00 CEUX
GENMAB A/S 26-Mar-25 1:41:40 PM 14 1363.00 XCSE
GENMAB A/S 26-Mar-25 1:42:28 PM 41 1363.50 AQEU
GENMAB A/S 26-Mar-25 1:43:08 PM 35 1363.50 CEUX
GENMAB A/S 26-Mar-25 1:44:48 PM 50 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:44:48 PM 26 1367.50 TQEX
GENMAB A/S 26-Mar-25 1:44:49 PM 74 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:44:49 PM 35 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:44:49 PM 56 1366.00 CEUX
GENMAB A/S 26-Mar-25 1:44:54 PM 75 1365.00 XCSE
GENMAB A/S 26-Mar-25 1:46:26 PM 26 1365.00 CEUX
GENMAB A/S 26-Mar-25 1:46:41 PM 74 1365.00 XCSE
GENMAB A/S 26-Mar-25 1:48:35 PM 34 1366.00 CEUX
GENMAB A/S 26-Mar-25 1:48:41 PM 2 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:48:41 PM 8 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:49:03 PM 30 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:50:23 PM 75 1368.00 XCSE

25

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 1:50:23 PM 28 1368.00 CEUX
GENMAB A/S 26-Mar-25 1:50:23 PM 42 1368.00 TQEX
GENMAB A/S 26-Mar-25 1:50:23 PM 41 1368.00 AQEU
GENMAB A/S 26-Mar-25 1:50:25 PM 19 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:50:25 PM 25 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:50:25 PM 2 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:50:25 PM 1 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:50:25 PM 74 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:50:25 PM 23 1368.00 CEUX
GENMAB A/S 26-Mar-25 1:51:25 PM 11 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:51:25 PM 2 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:51:25 PM 12 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:51:25 PM 2 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:51:25 PM 2 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:51:34 PM 29 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:52:05 PM 17 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:52:05 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:52:05 PM 30 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:52:05 PM 8 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:52:05 PM 4 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:52:55 PM 2 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:52:57 PM 18 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:53:11 PM 6 1366.50 CEUX
GENMAB A/S 26-Mar-25 1:53:15 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:53:15 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:53:15 PM 2 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:53:37 PM 18 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:54:03 PM 1 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 1 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 18 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:15 PM 18 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:54:55 PM 14 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:54:55 PM 18 1367.00 XCSE
GENMAB A/S 26-Mar-25 1:55:28 PM 5 1369.00 XCSE
GENMAB A/S 26-Mar-25 1:55:28 PM 72 1369.00 XCSE
GENMAB A/S 26-Mar-25 1:55:28 PM 18 1369.00 XCSE
GENMAB A/S 26-Mar-25 1:55:28 PM 40 1369.50 CEUX
GENMAB A/S 26-Mar-25 1:55:28 PM 12 1369.50 CEUX
GENMAB A/S 26-Mar-25 1:55:28 PM 22 1369.00 TQEX
GENMAB A/S 26-Mar-25 1:55:42 PM 48 1368.50 CEUX
GENMAB A/S 26-Mar-25 1:56:55 PM 73 1368.50 XCSE
GENMAB A/S 26-Mar-25 1:56:55 PM 18 1368.50 XCSE

26

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 1:56:55 PM 1 1368.50 XCSE
GENMAB A/S 26-Mar-25 1:56:55 PM 4 1368.50 XCSE
GENMAB A/S 26-Mar-25 1:56:55 PM 40 1368.00 AQEU
GENMAB A/S 26-Mar-25 1:57:31 PM 55 1367.50 CEUX
GENMAB A/S 26-Mar-25 1:58:25 PM 8 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:58:25 PM 3 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:58:25 PM 3 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:25 PM 15 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:25 PM 2 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:25 PM 39 1368.00 CEUX
GENMAB A/S 26-Mar-25 1:59:26 PM 12 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:26 PM 11 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:26 PM 17 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:26 PM 18 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:26 PM 3 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:26 PM 4 1368.00 XCSE
GENMAB A/S 26-Mar-25 1:59:47 PM 70 1367.50 XCSE
GENMAB A/S 26-Mar-25 1:59:47 PM 44 1367.00 CEUX
GENMAB A/S 26-Mar-25 1:59:47 PM 39 1367.50 TQEX
GENMAB A/S 26-Mar-25 1:59:49 PM 49 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:59:49 PM 23 1366.50 XCSE
GENMAB A/S 26-Mar-25 1:59:49 PM 25 1366.00 CEUX
GENMAB A/S 26-Mar-25 2:00:32 PM 75 1366.00 XCSE
GENMAB A/S 26-Mar-25 2:00:32 PM 30 1366.00 CEUX
GENMAB A/S 26-Mar-25 2:01:36 PM 71 1366.00 XCSE
GENMAB A/S 26-Mar-25 2:03:52 PM 30 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:03:52 PM 40 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:04:34 PM 23 1365.00 CEUX
GENMAB A/S 26-Mar-25 2:06:32 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:32 PM 12 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:32 PM 8 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:32 PM 13 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:32 PM 16 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:32 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:33 PM 23 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 48 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 6 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 37 1364.50 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 8 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 7 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:06:44 PM 15 1364.00 CEUX
GENMAB A/S 26-Mar-25 2:06:44 PM 10 1364.00 CEUX
GENMAB A/S 26-Mar-25 2:06:49 PM 36 1363.50 TQEX
GENMAB A/S 26-Mar-25 2:06:49 PM 5 1363.50 TQEX
GENMAB A/S 26-Mar-25 2:06:49 PM 39 1363.50 AQEU

27

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:07:26 PM 74 1363.00 XCSE
GENMAB A/S 26-Mar-25 2:08:34 PM 71 1363.00 XCSE
GENMAB A/S 26-Mar-25 2:08:34 PM 23 1363.00 CEUX
GENMAB A/S 26-Mar-25 2:09:50 PM 72 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:10:25 PM 75 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:11:09 PM 75 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:11:17 PM 41 1363.50 AQEU
GENMAB A/S 26-Mar-25 2:11:18 PM 72 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:11:18 PM 72 1363.00 CEUX
GENMAB A/S 26-Mar-25 2:11:18 PM 20 1363.00 TQEX
GENMAB A/S 26-Mar-25 2:11:18 PM 19 1363.00 TQEX
GENMAB A/S 26-Mar-25 2:12:34 PM 39 1361.50 CEUX
GENMAB A/S 26-Mar-25 2:13:25 PM 42 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:13:25 PM 4 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:13:25 PM 10 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:13:25 PM 12 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:13:25 PM 71 1361.00 XCSE
GENMAB A/S 26-Mar-25 2:13:25 PM 26 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:13:33 PM 69 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:13:33 PM 62 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:15:12 PM 69 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:15:12 PM 40 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:15:16 PM 2 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:15:16 PM 13 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:16:57 PM 69 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:16:57 PM 40 1363.00 AQEU
GENMAB A/S 26-Mar-25 2:17:27 PM 72 1366.00 XCSE
GENMAB A/S 26-Mar-25 2:17:27 PM 6 1366.00 CEUX
GENMAB A/S 26-Mar-25 2:17:27 PM 75 1366.00 CEUX
GENMAB A/S 26-Mar-25 2:17:27 PM 47 1366.00 CEUX
GENMAB A/S 26-Mar-25 2:17:27 PM 41 1366.00 TQEX
GENMAB A/S 26-Mar-25 2:17:41 PM 6 1365.50 CEUX
GENMAB A/S 26-Mar-25 2:17:41 PM 21 1365.50 CEUX
GENMAB A/S 26-Mar-25 2:17:44 PM 74 1365.00 XCSE
GENMAB A/S 26-Mar-25 2:17:54 PM 71 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:18:25 PM 72 1364.00 XCSE
GENMAB A/S 26-Mar-25 2:19:09 PM 73 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:19:09 PM 38 1363.50 CEUX
GENMAB A/S 26-Mar-25 2:19:09 PM 2 1363.50 CEUX
GENMAB A/S 26-Mar-25 2:19:49 PM 23 1363.00 CEUX
GENMAB A/S 26-Mar-25 2:19:59 PM 74 1364.50 XCSE
GENMAB A/S 26-Mar-25 2:20:00 PM 16 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:20:14 PM 59 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:21:29 PM 73 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:21:29 PM 23 1362.50 CEUX

28

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:21:53 PM 75 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:21:53 PM 30 1363.50 CEUX
GENMAB A/S 26-Mar-25 2:22:19 PM 10 1364.00 CEUX
GENMAB A/S 26-Mar-25 2:22:19 PM 18 1364.00 CEUX
GENMAB A/S 26-Mar-25 2:22:19 PM 30 1364.00 TQEX
GENMAB A/S 26-Mar-25 2:22:54 PM 68 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:23:25 PM 42 1363.50 AQEU
GENMAB A/S 26-Mar-25 2:23:52 PM 72 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:23:52 PM 32 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:24:40 PM 70 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:25:12 PM 1 1362.00 CEUX
GENMAB A/S 26-Mar-25 2:25:12 PM 27 1362.00 CEUX
GENMAB A/S 26-Mar-25 2:25:15 PM 8 1362.00 CEUX
GENMAB A/S 26-Mar-25 2:25:41 PM 65 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:25:41 PM 9 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:25:41 PM 43 1362.00 CEUX
GENMAB A/S 26-Mar-25 2:26:18 PM 75 1361.00 XCSE
GENMAB A/S 26-Mar-25 2:26:18 PM 71 1362.00 XCSE
GENMAB A/S 26-Mar-25 2:26:18 PM 23 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:26:18 PM 36 1362.00 CEUX
GENMAB A/S 26-Mar-25 2:26:18 PM 9 1360.50 TQEX
GENMAB A/S 26-Mar-25 2:26:18 PM 29 1361.50 TQEX
GENMAB A/S 26-Mar-25 2:26:19 PM 60 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:26:30 PM 25 1360.50 XCSE
GENMAB A/S 26-Mar-25 2:26:30 PM 30 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:27:30 PM 70 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:27:30 PM 31 1363.50 CEUX
GENMAB A/S 26-Mar-25 2:27:55 PM 5 1364.50 XCSE
GENMAB A/S 26-Mar-25 2:27:55 PM 66 1364.50 XCSE
GENMAB A/S 26-Mar-25 2:27:55 PM 21 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:27:55 PM 10 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:27:55 PM 31 1364.50 AQEU
GENMAB A/S 26-Mar-25 2:29:33 PM 71 1364.50 XCSE
GENMAB A/S 26-Mar-25 2:29:33 PM 5 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:29:33 PM 2 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:29:33 PM 34 1364.50 CEUX
GENMAB A/S 26-Mar-25 2:29:52 PM 15 1364.00 AQEU
GENMAB A/S 26-Mar-25 2:29:52 PM 9 1364.00 AQEU
GENMAB A/S 26-Mar-25 2:30:00 PM 1 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:30:00 PM 15 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:30:00 PM 55 1363.50 XCSE
GENMAB A/S 26-Mar-25 2:30:00 PM 25 1363.50 CEUX
GENMAB A/S 26-Mar-25 2:30:02 PM 23 1363.00 TQEX
GENMAB A/S 26-Mar-25 2:30:10 PM 19 1362.50 XCSE
GENMAB A/S 26-Mar-25 2:30:10 PM 53 1362.50 XCSE

29

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:30:10 PM 14 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:30:10 PM 9 1362.50 CEUX
GENMAB A/S 26-Mar-25 2:30:11 PM 72 1361.00 XCSE
GENMAB A/S 26-Mar-25 2:30:11 PM 44 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:30:11 PM 6 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:30:12 PM 23 1359.50 XCSE
GENMAB A/S 26-Mar-25 2:30:12 PM 50 1359.50 XCSE
GENMAB A/S 26-Mar-25 2:30:12 PM 43 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:30:13 PM 52 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:30:41 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:30:41 PM 22 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:30:41 PM 34 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:30:41 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:30:42 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 2:30:42 PM 3 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:30:42 PM 8 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:30:42 PM 12 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:30:47 PM 10 1362.00 TQEX
GENMAB A/S 26-Mar-25 2:30:48 PM 15 1362.00 TQEX
GENMAB A/S 26-Mar-25 2:30:48 PM 3 1362.00 AQEU
GENMAB A/S 26-Mar-25 2:30:48 PM 21 1362.00 AQEU
GENMAB A/S 26-Mar-25 2:31:10 PM 57 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:31:10 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:31:10 PM 35 1361.50 CEUX
GENMAB A/S 26-Mar-25 2:31:13 PM 18 1360.50 XCSE
GENMAB A/S 26-Mar-25 2:31:13 PM 33 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:31:18 PM 48 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:31:18 PM 25 1359.50 CEUX
GENMAB A/S 26-Mar-25 2:31:18 PM 34 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:31:19 PM 42 1358.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 31 1358.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 3 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 7 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 60 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 1 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:31:31 PM 33 1357.00 CEUX
GENMAB A/S 26-Mar-25 2:31:31 PM 12 1357.00 AQEU
GENMAB A/S 26-Mar-25 2:31:35 PM 26 1358.50 TQEX
GENMAB A/S 26-Mar-25 2:32:10 PM 22 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:32:10 PM 17 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:32:10 PM 68 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:32:10 PM 62 1358.00 XCSE
GENMAB A/S 26-Mar-25 2:32:10 PM 24 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:32:10 PM 30 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:32:10 PM 29 1357.00 AQEU

30

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:33:01 PM 23 1358.00 TQEX
GENMAB A/S 26-Mar-25 2:33:14 PM 74 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:33:27 PM 17 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:33:27 PM 10 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:33:27 PM 72 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:33:27 PM 21 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:33:27 PM 25 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:33:27 PM 23 1357.50 TQEX
GENMAB A/S 26-Mar-25 2:33:27 PM 23 1358.00 AQEU
GENMAB A/S 26-Mar-25 2:34:25 PM 74 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 22 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 10 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 20 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 50 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 11 1355.50 XCSE
GENMAB A/S 26-Mar-25 2:34:25 PM 33 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 1 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 4 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 2 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 2 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 1 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 1 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 16 1355.00 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 20 1355.00 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 2 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 1 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:25 PM 11 1355.50 TQEX
GENMAB A/S 26-Mar-25 2:34:25 PM 24 1355.50 AQEU
GENMAB A/S 26-Mar-25 2:34:25 PM 14 1355.50 AQEU
GENMAB A/S 26-Mar-25 2:34:26 PM 39 1355.50 XCSE
GENMAB A/S 26-Mar-25 2:34:27 PM 23 1355.50 XCSE
GENMAB A/S 26-Mar-25 2:34:27 PM 59 1355.50 CEUX
GENMAB A/S 26-Mar-25 2:34:57 PM 20 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:57 PM 30 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:57 PM 10 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:57 PM 12 1355.00 XCSE
GENMAB A/S 26-Mar-25 2:34:59 PM 12 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:34:59 PM 10 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:34:59 PM 20 1354.00 CEUX
GENMAB A/S 26-Mar-25 2:34:59 PM 6 1354.00 CEUX
GENMAB A/S 26-Mar-25 2:35:00 PM 20 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:35:30 PM 32 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:35:31 PM 42 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:35:31 PM 20 1353.50 XCSE
GENMAB A/S 26-Mar-25 2:35:31 PM 20 1354.00 XCSE

31

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:35:31 PM 45 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:35:31 PM 30 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:35:31 PM 49 1354.00 CEUX
GENMAB A/S 26-Mar-25 2:35:31 PM 29 1354.00 TQEX
GENMAB A/S 26-Mar-25 2:35:31 PM 23 1354.00 AQEU
GENMAB A/S 26-Mar-25 2:35:41 PM 11 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:35:41 PM 3 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:35:41 PM 42 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:35:41 PM 12 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:35:41 PM 21 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:35:41 PM 2 1354.50 XCSE
GENMAB A/S 26-Mar-25 2:36:21 PM 30 1353.00 XCSE
GENMAB A/S 26-Mar-25 2:36:21 PM 75 1354.00 XCSE
GENMAB A/S 26-Mar-25 2:36:21 PM 45 1353.00 XCSE
GENMAB A/S 26-Mar-25 2:36:21 PM 71 1352.50 CEUX
GENMAB A/S 26-Mar-25 2:36:21 PM 69 1353.50 CEUX
GENMAB A/S 26-Mar-25 2:36:21 PM 24 1352.50 TQEX
GENMAB A/S 26-Mar-25 2:36:27 PM 57 1353.00 CEUX
GENMAB A/S 26-Mar-25 2:36:30 PM 71 1352.50 XCSE
GENMAB A/S 26-Mar-25 2:36:31 PM 73 1352.00 CEUX
GENMAB A/S 26-Mar-25 2:36:43 PM 71 1351.50 XCSE
GENMAB A/S 26-Mar-25 2:37:04 PM 69 1353.50 XCSE
GENMAB A/S 26-Mar-25 2:37:13 PM 23 1353.50 AQEU
GENMAB A/S 26-Mar-25 2:37:44 PM 1 1353.00 CEUX
GENMAB A/S 26-Mar-25 2:37:44 PM 23 1353.00 CEUX
GENMAB A/S 26-Mar-25 2:37:48 PM 72 1352.50 XCSE
GENMAB A/S 26-Mar-25 2:37:48 PM 8 1352.00 CEUX
GENMAB A/S 26-Mar-25 2:37:48 PM 15 1352.00 CEUX
GENMAB A/S 26-Mar-25 2:37:48 PM 25 1352.00 TQEX
GENMAB A/S 26-Mar-25 2:38:53 PM 16 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:38:53 PM 2 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:01 PM 42 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:01 PM 10 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:01 PM 30 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:01 PM 23 1357.50 AQEU
GENMAB A/S 26-Mar-25 2:39:02 PM 17 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:02 PM 10 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:02 PM 9 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:02 PM 11 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:02 PM 69 1357.00 CEUX
GENMAB A/S 26-Mar-25 2:39:14 PM 69 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:39:15 PM 10 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:39:15 PM 14 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:39:15 PM 48 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:39:15 PM 43 1357.00 TQEX

32

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:39:21 PM 2 1356.00 CEUX
GENMAB A/S 26-Mar-25 2:39:22 PM 71 1356.00 CEUX
GENMAB A/S 26-Mar-25 2:39:32 PM 11 1355.50 XCSE
GENMAB A/S 26-Mar-25 2:39:59 PM 9 1357.00 AQEU
GENMAB A/S 26-Mar-25 2:40:03 PM 10 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:40:15 PM 10 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:40:31 PM 9 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:40:35 PM 11 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:40:44 PM 72 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:40:44 PM 75 1358.00 CEUX
GENMAB A/S 26-Mar-25 2:41:05 PM 38 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:41:05 PM 4 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:41:05 PM 11 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:41:05 PM 19 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:41:05 PM 22 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:41:33 PM 42 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:41:33 PM 2 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:41:51 PM 72 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:41:51 PM 9 1359.50 CEUX
GENMAB A/S 26-Mar-25 2:41:51 PM 54 1359.50 CEUX
GENMAB A/S 26-Mar-25 2:41:51 PM 30 1359.50 AQEU
GENMAB A/S 26-Mar-25 2:41:52 PM 7 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:41:54 PM 9 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:41:54 PM 16 1358.50 TQEX
GENMAB A/S 26-Mar-25 2:42:23 PM 4 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:42:23 PM 2 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:42:23 PM 63 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:42:23 PM 15 1359.00 AQEU
GENMAB A/S 26-Mar-25 2:42:27 PM 15 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:42:27 PM 24 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:43:11 PM 3 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:11 PM 11 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:25 PM 44 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:25 PM 50 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:25 PM 57 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:43:26 PM 19 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:26 PM 75 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:43:56 PM 10 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:44:04 PM 10 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:44:04 PM 10 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:44:04 PM 37 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:44:27 PM 23 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:44:27 PM 31 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:44:27 PM 10 1358.00 XCSE
GENMAB A/S 26-Mar-25 2:44:27 PM 42 1358.00 XCSE

33

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:44:27 PM 11 1358.00 XCSE
GENMAB A/S 26-Mar-25 2:44:27 PM 44 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:44:27 PM 10 1358.00 CEUX
GENMAB A/S 26-Mar-25 2:44:27 PM 17 1358.00 CEUX
GENMAB A/S 26-Mar-25 2:44:27 PM 23 1358.50 TQEX
GENMAB A/S 26-Mar-25 2:44:27 PM 26 1359.00 AQEU
GENMAB A/S 26-Mar-25 2:45:13 PM 12 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 3 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 4 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 56 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 11 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 16 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:13 PM 10 1358.50 XCSE
GENMAB A/S 26-Mar-25 2:45:26 PM 3 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:26 PM 10 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:26 PM 10 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:45 PM 42 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:45 PM 10 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:45 PM 3 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:45 PM 23 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:45 PM 16 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:45:49 PM 5 1358.50 TQEX
GENMAB A/S 26-Mar-25 2:47:06 PM 10 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:47:06 PM 42 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:47:06 PM 11 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:47:06 PM 68 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:48:12 PM 74 1359.50 XCSE
GENMAB A/S 26-Mar-25 2:48:12 PM 24 1359.50 TQEX
GENMAB A/S 26-Mar-25 2:48:12 PM 35 1359.50 AQEU
GENMAB A/S 26-Mar-25 2:48:24 PM 2 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:48:24 PM 9 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:48:24 PM 5 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:48:24 PM 2 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:48:24 PM 4 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:49:27 PM 69 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:49:51 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:49:51 PM 19 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:49:51 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:50:04 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:50:41 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:50:41 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:50:45 PM 8 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:52:26 PM 1 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:53:28 PM 65 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:53:28 PM 7 1361.50 XCSE

34

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:53:28 PM 36 1361.50 CEUX
GENMAB A/S 26-Mar-25 2:53:46 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:53:46 PM 9 1361.50 CEUX
GENMAB A/S 26-Mar-25 2:53:51 PM 69 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:53:52 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:53:52 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:07 PM 14 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:07 PM 28 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 71 1360.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 24 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 1 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 72 1359.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 28 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 2:54:26 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 75 1359.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 14 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 58 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 2:54:26 PM 10 1360.00 TQEX
GENMAB A/S 26-Mar-25 2:54:26 PM 16 1360.00 TQEX
GENMAB A/S 26-Mar-25 2:54:26 PM 24 1361.00 TQEX
GENMAB A/S 26-Mar-25 2:54:26 PM 28 1360.50 AQEU
GENMAB A/S 26-Mar-25 2:55:21 PM 1 1359.50 CEUX
GENMAB A/S 26-Mar-25 2:55:40 PM 24 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:55:40 PM 7 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:55:40 PM 3 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:55:40 PM 2 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:55:40 PM 10 1360.00 CEUX
GENMAB A/S 26-Mar-25 2:55:48 PM 17 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:55:59 PM 42 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:55:59 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:55:59 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:56:00 PM 1 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:56:00 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:56:00 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:56:13 PM 72 1361.00 XCSE
GENMAB A/S 26-Mar-25 2:56:13 PM 9 1361.00 AQEU
GENMAB A/S 26-Mar-25 2:56:13 PM 26 1361.00 AQEU
GENMAB A/S 26-Mar-25 2:56:16 PM 74 1360.00 XCSE
GENMAB A/S 26-Mar-25 2:56:16 PM 10 1359.00 XCSE

35

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:56:16 PM 32 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:56:16 PM 11 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:56:16 PM 30 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:56:16 PM 70 1359.50 CEUX
GENMAB A/S 26-Mar-25 2:56:16 PM 34 1360.50 CEUX
GENMAB A/S 26-Mar-25 2:56:16 PM 36 1361.00 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 4 1359.50 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 8 1358.50 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 10 1359.50 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 10 1359.50 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 7 1359.50 TQEX
GENMAB A/S 26-Mar-25 2:56:16 PM 35 1360.00 AQEU
GENMAB A/S 26-Mar-25 2:56:21 PM 63 1359.00 XCSE
GENMAB A/S 26-Mar-25 2:56:25 PM 20 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:25 PM 8 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:25 PM 20 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:25 PM 10 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:25 PM 2 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:25 PM 15 1358.50 CEUX
GENMAB A/S 26-Mar-25 2:56:37 PM 47 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:56:37 PM 22 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:56:37 PM 6 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:56:37 PM 14 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:56:37 PM 40 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:56:37 PM 11 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:56:37 PM 7 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:56:37 PM 3 1357.50 CEUX
GENMAB A/S 26-Mar-25 2:56:45 PM 6 1356.00 CEUX
GENMAB A/S 26-Mar-25 2:56:50 PM 7 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:56:50 PM 20 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:56:50 PM 32 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:56:50 PM 10 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:56:50 PM 30 1356.00 CEUX
GENMAB A/S 26-Mar-25 2:57:10 PM 23 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:57:10 PM 17 1357.00 CEUX
GENMAB A/S 26-Mar-25 2:57:10 PM 18 1357.00 CEUX
GENMAB A/S 26-Mar-25 2:57:10 PM 25 1357.00 AQEU
GENMAB A/S 26-Mar-25 2:57:13 PM 19 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:57:13 PM 42 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:57:13 PM 49 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:57:13 PM 14 1356.00 CEUX
GENMAB A/S 26-Mar-25 2:57:18 PM 42 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:57:18 PM 6 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:57:18 PM 19 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:57:18 PM 19 1356.00 CEUX

36

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 2:57:56 PM 67 1356.00 XCSE
GENMAB A/S 26-Mar-25 2:58:20 PM 4 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:58:20 PM 1 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:58:28 PM 20 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:28 PM 27 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:28 PM 10 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:58:30 PM 10 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:58:31 PM 12 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 42 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 33 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 29 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 8 1356.50 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 11 1357.00 XCSE
GENMAB A/S 26-Mar-25 2:58:31 PM 8 1356.50 CEUX
GENMAB A/S 26-Mar-25 2:58:31 PM 23 1356.50 TQEX
GENMAB A/S 26-Mar-25 2:58:58 PM 31 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:58:58 PM 11 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:58:58 PM 42 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:58:58 PM 10 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:58:59 PM 10 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:58:59 PM 12 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 42 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 11 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 42 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 11 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 12 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:00 PM 12 1357.50 XCSE
GENMAB A/S 26-Mar-25 2:59:01 PM 8 1356.50 XCSE
GENMAB A/S 26-Mar-25 3:00:00 PM 75 1357.50 XCSE
GENMAB A/S 26-Mar-25 3:00:00 PM 10 1357.00 CEUX
GENMAB A/S 26-Mar-25 3:01:16 PM 25 1358.50 XCSE
GENMAB A/S 26-Mar-25 3:01:16 PM 10 1358.00 CEUX
GENMAB A/S 26-Mar-25 3:01:16 PM 10 1358.00 CEUX
GENMAB A/S 26-Mar-25 3:01:16 PM 20 1358.00 CEUX
GENMAB A/S 26-Mar-25 3:02:31 PM 74 1360.00 CEUX
GENMAB A/S 26-Mar-25 3:02:31 PM 23 1360.00 TQEX
GENMAB A/S 26-Mar-25 3:02:31 PM 34 1360.00 AQEU
GENMAB A/S 26-Mar-25 3:03:00 PM 4 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:03:00 PM 70 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:03:35 PM 74 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:04:12 PM 9 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:04:12 PM 8 1361.00 AQEU
GENMAB A/S 26-Mar-25 3:05:30 PM 3 1361.00 AQEU
GENMAB A/S 26-Mar-25 3:06:03 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:06:34 PM 4 1361.50 CEUX

37

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:07:41 PM 1 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:07:41 PM 10 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:07:54 PM 39 1362.00 TQEX
GENMAB A/S 26-Mar-25 3:07:54 PM 41 1362.00 AQEU
GENMAB A/S 26-Mar-25 3:07:55 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:08:23 PM 7 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:08:23 PM 3 1362.00 TQEX
GENMAB A/S 26-Mar-25 3:08:23 PM 20 1362.00 TQEX
GENMAB A/S 26-Mar-25 3:08:58 PM 10 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:08:59 PM 10 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:09:01 PM 38 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:09:01 PM 1 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:09:01 PM 7 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:09:15 PM 6 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:09:49 PM 35 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:10:05 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 66 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 15 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 27 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 71 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 71 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:10:05 PM 36 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:10:05 PM 69 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:10:05 PM 1 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:10:05 PM 7 1360.00 TQEX
GENMAB A/S 26-Mar-25 3:10:05 PM 26 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:10:05 PM 15 1362.00 TQEX
GENMAB A/S 26-Mar-25 3:10:05 PM 12 1362.00 TQEX
GENMAB A/S 26-Mar-25 3:10:05 PM 31 1362.00 AQEU
GENMAB A/S 26-Mar-25 3:10:05 PM 19 1361.00 AQEU
GENMAB A/S 26-Mar-25 3:10:08 PM 28 1360.50 CEUX
GENMAB A/S 26-Mar-25 3:10:28 PM 7 1360.00 CEUX
GENMAB A/S 26-Mar-25 3:10:31 PM 20 1360.00 CEUX
GENMAB A/S 26-Mar-25 3:10:53 PM 2 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:11:23 PM 70 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:11:37 PM 10 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:11:37 PM 18 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:11:37 PM 11 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:11:37 PM 72 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:11:37 PM 42 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:11:44 PM 42 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:44 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:44 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:45 PM 11 1362.50 XCSE

38

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:11:45 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:45 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:45 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:11:45 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:12 PM 20 1362.00 AQEU
GENMAB A/S 26-Mar-25 3:12:17 PM 24 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:12:17 PM 24 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:12:17 PM 6 1362.00 AQEU
GENMAB A/S 26-Mar-25 3:12:30 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:30 PM 42 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:30 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:30 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:31 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:12:31 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:13:15 PM 2 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:50 PM 21 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:13:50 PM 1 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:13:50 PM 20 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:13:50 PM 32 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:13:58 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 30 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 42 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 70 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:13:58 PM 28 1362.50 TQEX
GENMAB A/S 26-Mar-25 3:13:59 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:59 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:59 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:13:59 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:14:01 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:15:10 PM 73 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:15:26 PM 4 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:15:26 PM 3 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:15:26 PM 74 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:15:26 PM 24 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:15:26 PM 27 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:17:03 PM 71 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:18:23 PM 42 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:18:23 PM 2 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:18:23 PM 10 1364.50 XCSE

39

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:18:23 PM 11 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:18:23 PM 33 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:18:23 PM 73 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:18:23 PM 2 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:18:23 PM 25 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:18:23 PM 8 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:18:23 PM 15 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:18:58 PM 5 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:18:59 PM 23 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:19:03 PM 36 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:19:05 PM 23 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:19:09 PM 22 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:19:26 PM 1 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:19:46 PM 12 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:19:46 PM 10 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:19:46 PM 13 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:19:53 PM 11 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:19:53 PM 2 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:20:02 PM 60 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:20:02 PM 14 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:20:02 PM 17 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:20:02 PM 33 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:20:47 PM 26 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:21:07 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 69 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 42 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 69 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 2 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 22 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:21:07 PM 36 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 4 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 3 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 32 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 68 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 4 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 25 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 2 1362.00 CEUX
GENMAB A/S 26-Mar-25 3:21:07 PM 9 1363.00 TQEX
GENMAB A/S 26-Mar-25 3:21:07 PM 16 1363.00 TQEX
GENMAB A/S 26-Mar-25 3:21:29 PM 10 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:21:44 PM 4 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:22:00 PM 24 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:22:00 PM 23 1363.50 CEUX

40

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:22:00 PM 10 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:22:00 PM 25 1363.00 AQEU
GENMAB A/S 26-Mar-25 3:22:33 PM 31 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:22:33 PM 69 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:22:33 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:22:33 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:23:02 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:24:03 PM 69 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:24:13 PM 23 1363.50 TQEX
GENMAB A/S 26-Mar-25 3:25:26 PM 3 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:25:26 PM 9 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:25:26 PM 1 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:25:26 PM 8 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:25:26 PM 15 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 30 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 42 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 1 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 72 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 33 1363.50 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:37 PM 1 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 10 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 4 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 10 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 2 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 10 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 20 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:25:37 PM 4 1363.50 CEUX
GENMAB A/S 26-Mar-25 3:25:42 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 12 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 30 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 11 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 10 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:25:42 PM 22 1362.50 CEUX
GENMAB A/S 26-Mar-25 3:26:17 PM 30 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 72 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 42 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 33 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 36 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 11 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 11 1362.00 XCSE
GENMAB A/S 26-Mar-25 3:26:17 PM 65 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:26:17 PM 6 1361.50 CEUX

41

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:26:17 PM 25 1362.50 TQEX
GENMAB A/S 26-Mar-25 3:26:17 PM 44 1362.50 AQEU
GENMAB A/S 26-Mar-25 3:28:25 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:25 PM 4 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:28:31 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 38 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 7 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:37 PM 15 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:28:37 PM 1 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:28:37 PM 10 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:28:38 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:38 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:38 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:38 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:38 PM 30 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:39 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:28:44 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:03 PM 12 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:29:03 PM 15 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:29:20 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:20 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:20 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:20 PM 24 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:20 PM 16 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:20 PM 38 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:29:20 PM 6 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:29:21 PM 40 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 40 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 40 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 4 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:21 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:29:23 PM 71 1360.50 XCSE

42

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:29:35 PM 1 1360.50 AQEU
GENMAB A/S 26-Mar-25 3:29:47 PM 2 1361.50 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 17 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:30:05 PM 71 1359.50 XCSE
GENMAB A/S 26-Mar-25 3:30:05 PM 69 1361.50 XCSE
GENMAB A/S 26-Mar-25 3:30:05 PM 28 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:30:05 PM 30 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:30:05 PM 72 1360.00 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 17 1359.50 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 50 1359.50 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 75 1361.00 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 7 1359.50 CEUX
GENMAB A/S 26-Mar-25 3:30:05 PM 23 1361.00 TQEX
GENMAB A/S 26-Mar-25 3:30:05 PM 3 1359.50 TQEX
GENMAB A/S 26-Mar-25 3:30:05 PM 31 1361.50 AQEU
GENMAB A/S 26-Mar-25 3:31:40 PM 18 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 4 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 18 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 30 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 1 1360.00 XCSE
GENMAB A/S 26-Mar-25 3:32:01 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 3:32:01 PM 23 1360.50 TQEX
GENMAB A/S 26-Mar-25 3:32:01 PM 1 1360.50 AQEU
GENMAB A/S 26-Mar-25 3:32:01 PM 27 1360.50 AQEU
GENMAB A/S 26-Mar-25 3:32:02 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 26 1360.50 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 32 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 6 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:02 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:04 PM 18 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:04 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:04 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:04 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:04 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:11 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:11 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:11 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:11 PM 17 1361.00 XCSE

43

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:32:11 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:26 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:26 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:26 PM 21 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:32:26 PM 25 1361.00 XCSE
GENMAB A/S 26-Mar-25 3:34:27 PM 73 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:34:27 PM 70 1363.00 CEUX
GENMAB A/S 26-Mar-25 3:34:56 PM 70 1363.00 XCSE
GENMAB A/S 26-Mar-25 3:36:25 PM 2 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:36:26 PM 2 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:36:27 PM 3 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:36:52 PM 6 1364.00 AQEU
GENMAB A/S 26-Mar-25 3:37:11 PM 36 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:38:20 PM 42 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:38:20 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:38:20 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:38:20 PM 13 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:38:20 PM 29 1366.00 TQEX
GENMAB A/S 26-Mar-25 3:38:20 PM 14 1365.00 TQEX
GENMAB A/S 26-Mar-25 3:39:37 PM 74 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:39:49 PM 13 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:39:49 PM 3 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:40:00 PM 35 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:40:00 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:40:00 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:40:00 PM 50 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:40:00 PM 20 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:40:00 PM 9 1365.00 TQEX
GENMAB A/S 26-Mar-25 3:40:00 PM 24 1366.00 TQEX
GENMAB A/S 26-Mar-25 3:40:00 PM 36 1366.00 AQEU
GENMAB A/S 26-Mar-25 3:40:29 PM 10 1365.00 AQEU
GENMAB A/S 26-Mar-25 3:41:26 PM 8 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:41:57 PM 2 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:41:57 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:41:57 PM 4 1365.50 CEUX
GENMAB A/S 26-Mar-25 3:42:25 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:25 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:25 PM 2 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:25 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:27 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:27 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:27 PM 2 1365.50 CEUX
GENMAB A/S 26-Mar-25 3:42:28 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:42:28 PM 5 1365.50 CEUX
GENMAB A/S 26-Mar-25 3:42:37 PM 94 1365.50 XCSE

44

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:43:26 PM 2 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:44:26 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:44:26 PM 36 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:44:27 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:44:27 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:44:27 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:44:27 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:44:27 PM 4 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:44:27 PM 4 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 42 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 12 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 72 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 29 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 69 1364.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 11 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:44:49 PM 7 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 5 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 8 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 6 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 2 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 7 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 8 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 18 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 15 1365.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 5 1364.50 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 2 1364.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 59 1365.00 CEUX
GENMAB A/S 26-Mar-25 3:44:49 PM 9 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:44:49 PM 7 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:44:49 PM 23 1364.00 TQEX
GENMAB A/S 26-Mar-25 3:44:49 PM 25 1365.50 TQEX
GENMAB A/S 26-Mar-25 3:44:49 PM 13 1365.00 AQEU
GENMAB A/S 26-Mar-25 3:44:50 PM 20 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:44:51 PM 50 1364.50 XCSE
GENMAB A/S 26-Mar-25 3:45:20 PM 3 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:45:20 PM 55 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:45:20 PM 17 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:45:20 PM 36 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:45:20 PM 37 1366.00 AQEU
GENMAB A/S 26-Mar-25 3:46:08 PM 72 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:46:08 PM 34 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:08 PM 40 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:20 PM 72 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:46:20 PM 71 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:46:20 PM 24 1367.50 TQEX

45

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:46:27 PM 9 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 8 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:46:58 PM 14 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:46:58 PM 42 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:46:58 PM 30 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:46:58 PM 75 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:46:58 PM 36 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 20 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 36 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 4 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 50 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:58 PM 17 1367.00 AQEU
GENMAB A/S 26-Mar-25 3:46:58 PM 6 1367.00 AQEU
GENMAB A/S 26-Mar-25 3:46:59 PM 42 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:46:59 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:46:59 PM 22 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:46:59 PM 4 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:46:59 PM 5 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:47:25 PM 2 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:47:25 PM 3 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:47:25 PM 3 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:05 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 11 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 40 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 10 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 2 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 10 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:48:05 PM 45 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:05 PM 24 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:05 PM 40 1367.00 TQEX
GENMAB A/S 26-Mar-25 3:48:05 PM 13 1367.00 AQEU
GENMAB A/S 26-Mar-25 3:48:05 PM 10 1367.00 AQEU
GENMAB A/S 26-Mar-25 3:48:11 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:11 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:11 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:11 PM 4 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:11 PM 36 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:11 PM 5 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:14 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:14 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:14 PM 4 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:14 PM 36 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:14 PM 4 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:48:23 PM 3 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:23 PM 7 1367.00 XCSE

46

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:48:23 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:23 PM 42 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:23 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:24 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:24 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:24 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:24 PM 7 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:24 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:25 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:26 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:26 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:26 PM 41 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:26 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:26 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:26 PM 5 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:27 PM 12 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:28 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:28 PM 42 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:28 PM 1 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:28 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:29 PM 70 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:48:29 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:29 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:29 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:48:29 PM 8 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 36 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 25 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 63 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 5 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:48:29 PM 12 1366.00 AQEU
GENMAB A/S 26-Mar-25 3:48:29 PM 11 1366.00 AQEU
GENMAB A/S 26-Mar-25 3:49:26 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:49:38 PM 27 1366.00 AQEU
GENMAB A/S 26-Mar-25 3:49:40 PM 29 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:49:40 PM 25 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:49:44 PM 12 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:49:44 PM 12 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:49:44 PM 10 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:49:44 PM 10 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:49:44 PM 1 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:50:14 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 21 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 16 1365.00 XCSE

47

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:50:50 PM 2 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 55 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 5 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 59 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 34 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 42 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 45 1365.00 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 3:50:50 PM 65 1365.00 CEUX
GENMAB A/S 26-Mar-25 3:50:50 PM 5 1365.00 CEUX
GENMAB A/S 26-Mar-25 3:50:50 PM 24 1364.50 AQEU
GENMAB A/S 26-Mar-25 3:51:52 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:51:52 PM 2 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:51:52 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:51:52 PM 41 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:04 PM 42 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:04 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:04 PM 42 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:04 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:04 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:05 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:05 PM 12 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:05 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:05 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:07 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:07 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:08 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:08 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:14 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:14 PM 42 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:14 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:15 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:15 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:21 PM 12 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:21 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:24 PM 4 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:52:49 PM 12 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:53:32 PM 74 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:53:32 PM 9 1366.50 TQEX
GENMAB A/S 26-Mar-25 3:53:32 PM 23 1366.50 TQEX
GENMAB A/S 26-Mar-25 3:53:32 PM 43 1366.50 AQEU
GENMAB A/S 26-Mar-25 3:53:59 PM 36 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:06 PM 9 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:06 PM 94 1367.00 XCSE

48

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:54:06 PM 34 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:06 PM 9 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:06 PM 42 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:07 PM 94 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:07 PM 94 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:07 PM 94 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 38 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 11 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 14 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 94 1367.00 XCSE
GENMAB A/S 26-Mar-25 3:54:08 PM 36 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:08 PM 5 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:08 PM 23 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:09 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:09 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:14 PM 8 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:14 PM 65 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:14 PM 10 1366.50 XCSE
GENMAB A/S 26-Mar-25 3:54:14 PM 36 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:14 PM 2 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:54:26 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:26 PM 30 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:54:26 PM 23 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:55:26 PM 10 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:55:30 PM 36 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:55:40 PM 22 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:55:45 PM 66 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:56:03 PM 13 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:56:13 PM 32 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:56:14 PM 4 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:56:14 PM 5 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:56:21 PM 2 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:56:21 PM 71 1366.00 CEUX
GENMAB A/S 26-Mar-25 3:56:25 PM 2 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:25 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:25 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:25 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:26 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:26 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:27 PM 20 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:27 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:27 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:27 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:27 PM 12 1366.00 XCSE

49

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 3:56:34 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:34 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:56:34 PM 1 1366.00 XCSE
GENMAB A/S 26-Mar-25 3:58:05 PM 12 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:05 PM 8 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:05 PM 10 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:05 PM 12 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:06 PM 10 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:09 PM 59 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:58:34 PM 45 1367.00 CEUX
GENMAB A/S 26-Mar-25 3:59:12 PM 34 1366.50 CEUX
GENMAB A/S 26-Mar-25 3:59:59 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:59:59 PM 49 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:59:59 PM 11 1367.50 XCSE
GENMAB A/S 26-Mar-25 3:59:59 PM 9 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:59:59 PM 24 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:59:59 PM 27 1367.50 CEUX
GENMAB A/S 26-Mar-25 3:59:59 PM 6 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:00:00 PM 10 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:00 PM 10 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:03 PM 65 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:03 PM 2 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:03 PM 16 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:00:03 PM 58 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:00:04 PM 30 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:05 PM 1 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:05 PM 1 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:00:09 PM 18 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:01:00 PM 71 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:01:01 PM 65 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:01:01 PM 12 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:01:01 PM 17 1368.50 AQEU
GENMAB A/S 26-Mar-25 4:01:01 PM 13 1368.50 AQEU
GENMAB A/S 26-Mar-25 4:01:25 PM 32 1368.50 CEUX
GENMAB A/S 26-Mar-25 4:01:26 PM 23 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:01:28 PM 12 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:01:28 PM 10 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:01:28 PM 9 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:01 PM 2 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:01 PM 24 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:01 PM 39 1369.00 CEUX
GENMAB A/S 26-Mar-25 4:02:01 PM 34 1369.00 CEUX
GENMAB A/S 26-Mar-25 4:02:01 PM 41 1369.00 TQEX
GENMAB A/S 26-Mar-25 4:02:01 PM 34 1369.00 AQEU
GENMAB A/S 26-Mar-25 4:02:12 PM 30 1369.00 XCSE

50

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:02:12 PM 41 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:02:12 PM 39 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:12 PM 25 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:12 PM 34 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:02:34 PM 58 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:34 PM 10 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:34 PM 26 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:34 PM 23 1368.50 CEUX
GENMAB A/S 26-Mar-25 4:02:36 PM 11 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:02:36 PM 12 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:03:13 PM 26 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:03:13 PM 12 1369.00 XCSE
GENMAB A/S 26-Mar-25 4:03:13 PM 72 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:03:26 PM 29 1368.50 CEUX
GENMAB A/S 26-Mar-25 4:03:27 PM 2 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:03:41 PM 50 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:03:41 PM 22 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:03:41 PM 50 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:03:41 PM 1 1368.00 CEUX
GENMAB A/S 26-Mar-25 4:03:41 PM 73 1368.00 CEUX
GENMAB A/S 26-Mar-25 4:03:41 PM 15 1368.00 TQEX
GENMAB A/S 26-Mar-25 4:03:41 PM 21 1368.00 TQEX
GENMAB A/S 26-Mar-25 4:03:41 PM 30 1368.00 AQEU
GENMAB A/S 26-Mar-25 4:03:56 PM 1 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:03:56 PM 69 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:03:56 PM 22 1367.00 TQEX
GENMAB A/S 26-Mar-25 4:03:56 PM 33 1367.50 AQEU
GENMAB A/S 26-Mar-25 4:03:57 PM 9 1367.00 TQEX
GENMAB A/S 26-Mar-25 4:04:05 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:05 PM 64 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:05 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:05 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:06 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:06 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:06 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:06 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:06 PM 1 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:04:06 PM 1 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:04:07 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 75 1366.50 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 2 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 10 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:07 PM 10 1367.00 XCSE

51

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:04:07 PM 34 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:04:08 PM 25 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 34 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 30 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 13 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 25 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:08 PM 15 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:09 PM 52 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:09 PM 12 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:09 PM 19 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:09 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:15 PM 7 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:15 PM 65 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:15 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:15 PM 11 1367.00 XCSE
GENMAB A/S 26-Mar-25 4:04:22 PM 1 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:04:22 PM 35 1366.00 TQEX
GENMAB A/S 26-Mar-25 4:05:26 PM 10 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:05:26 PM 49 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:06:21 PM 34 1368.00 AQEU
GENMAB A/S 26-Mar-25 4:06:26 PM 24 1368.00 CEUX
GENMAB A/S 26-Mar-25 4:06:26 PM 30 1368.00 CEUX
GENMAB A/S 26-Mar-25 4:06:48 PM 10 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:06:48 PM 2 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:06:48 PM 11 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:06:48 PM 37 1368.50 XCSE
GENMAB A/S 26-Mar-25 4:07:03 PM 47 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:07:03 PM 25 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:07:03 PM 42 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:07:03 PM 27 1367.50 TQEX
GENMAB A/S 26-Mar-25 4:07:03 PM 15 1367.50 TQEX
GENMAB A/S 26-Mar-25 4:07:25 PM 4 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:13 PM 2 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:13 PM 23 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:15 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:08:15 PM 2 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:08:15 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:08:15 PM 36 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:20 PM 3 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:29 PM 23 1367.50 AQEU
GENMAB A/S 26-Mar-25 4:08:31 PM 11 1367.50 XCSE

52

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:08:31 PM 12 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:08:31 PM 36 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:08:31 PM 4 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:09:26 PM 74 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:09:26 PM 2 1367.50 XCSE
GENMAB A/S 26-Mar-25 4:09:26 PM 75 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:09:26 PM 52 1367.50 CEUX
GENMAB A/S 26-Mar-25 4:09:26 PM 27 1367.50 TQEX
GENMAB A/S 26-Mar-25 4:10:24 PM 1 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:10:25 PM 1 1366.50 XCSE
GENMAB A/S 26-Mar-25 4:10:30 PM 1 1367.00 TQEX
GENMAB A/S 26-Mar-25 4:10:30 PM 6 1367.00 TQEX
GENMAB A/S 26-Mar-25 4:10:30 PM 27 1367.00 TQEX
GENMAB A/S 26-Mar-25 4:10:47 PM 36 1367.00 CEUX
GENMAB A/S 26-Mar-25 4:10:47 PM 29 1367.00 CEUX
GENMAB A/S 26-Mar-25 4:10:47 PM 40 1367.00 AQEU
GENMAB A/S 26-Mar-25 4:10:51 PM 1 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:10:56 PM 34 1366.50 XCSE
GENMAB A/S 26-Mar-25 4:10:56 PM 8 1366.50 XCSE
GENMAB A/S 26-Mar-25 4:10:56 PM 26 1366.50 XCSE
GENMAB A/S 26-Mar-25 4:10:56 PM 9 1366.50 CEUX
GENMAB A/S 26-Mar-25 4:11:37 PM 54 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:11:37 PM 11 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:11:38 PM 3 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:11:38 PM 25 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:11:38 PM 7 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:12:12 PM 1 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 50 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 8 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 48 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 6 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:12 PM 44 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 1 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 48 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 3 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 9 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 10 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 12 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 3 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:13 PM 9 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:15 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:15 PM 10 1366.00 XCSE

53

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:12:18 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:18 PM 11 1366.00 XCSE
GENMAB A/S 26-Mar-25 4:12:18 PM 2 1366.00 CEUX
GENMAB A/S 26-Mar-25 4:12:18 PM 12 1366.00 CEUX
GENMAB A/S 26-Mar-25 4:12:18 PM 33 1366.00 CEUX
GENMAB A/S 26-Mar-25 4:12:18 PM 6 1366.00 CEUX
GENMAB A/S 26-Mar-25 4:13:05 PM 41 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:13:05 PM 34 1365.50 CEUX
GENMAB A/S 26-Mar-25 4:13:11 PM 24 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:11 PM 22 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:11 PM 48 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 5 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:12 PM 30 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:13 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:13 PM 3 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:13 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 3 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:14 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:16 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:16 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:16 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:16 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:18 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:19 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:22 PM 75 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:22 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:22 PM 32 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:22 PM 50 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 34 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 31 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 23 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 18 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:13:23 PM 10 1365.50 XCSE

54

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:13:23 PM 36 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 1 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 42 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 35 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 13 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 23 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 35 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 11 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:26 PM 12 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:27 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:27 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:35 PM 2 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:35 PM 17 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:13:44 PM 27 1365.00 CEUX
GENMAB A/S 26-Mar-25 4:13:44 PM 20 1365.00 CEUX
GENMAB A/S 26-Mar-25 4:13:45 PM 10 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:14:26 PM 2 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:14:26 PM 29 1365.00 CEUX
GENMAB A/S 26-Mar-25 4:14:31 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:14:31 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:14:33 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:14:33 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:01 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:01 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:03 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:03 PM 2 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:03 PM 7 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:04 PM 9 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:11 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:11 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:12 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:12 PM 48 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:12 PM 11 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:16 PM 10 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:16 PM 48 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:19 PM 12 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:23 PM 23 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:24 PM 1 1365.50 XCSE
GENMAB A/S 26-Mar-25 4:15:24 PM 20 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:15:24 PM 51 1365.00 XCSE
GENMAB A/S 26-Mar-25 4:15:24 PM 73 1365.00 CEUX
GENMAB A/S 26-Mar-25 4:15:24 PM 1 1365.00 AQEU
GENMAB A/S 26-Mar-25 4:15:24 PM 7 1365.00 AQEU
GENMAB A/S 26-Mar-25 4:15:25 PM 8 1364.00 XCSE
GENMAB A/S 26-Mar-25 4:15:25 PM 10 1364.00 CEUX

55

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:15:25 PM 10 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:15:25 PM 2 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:15:25 PM 6 1365.00 AQEU
GENMAB A/S 26-Mar-25 4:15:25 PM 9 1365.00 AQEU
GENMAB A/S 26-Mar-25 4:16:10 PM 61 1364.00 XCSE
GENMAB A/S 26-Mar-25 4:16:10 PM 10 1364.50 XCSE
GENMAB A/S 26-Mar-25 4:16:10 PM 50 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:16:10 PM 34 1364.00 TQEX
GENMAB A/S 26-Mar-25 4:16:10 PM 10 1364.50 AQEU
GENMAB A/S 26-Mar-25 4:16:14 PM 7 1364.50 AQEU
GENMAB A/S 26-Mar-25 4:16:26 PM 5 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:16:39 PM 73 1364.00 XCSE
GENMAB A/S 26-Mar-25 4:16:39 PM 37 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:16:39 PM 34 1364.00 CEUX
GENMAB A/S 26-Mar-25 4:16:39 PM 26 1364.00 TQEX
GENMAB A/S 26-Mar-25 4:16:55 PM 48 1364.00 XCSE
GENMAB A/S 26-Mar-25 4:16:55 PM 11 1364.00 XCSE
GENMAB A/S 26-Mar-25 4:17:12 PM 71 1363.00 XCSE
GENMAB A/S 26-Mar-25 4:17:12 PM 68 1363.50 CEUX
GENMAB A/S 26-Mar-25 4:17:12 PM 25 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:17:12 PM 31 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:17:12 PM 7 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:17:12 PM 10 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:17:12 PM 41 1363.50 AQEU
GENMAB A/S 26-Mar-25 4:17:24 PM 27 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:17:24 PM 32 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:17:24 PM 8 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:17:24 PM 2 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:17:30 PM 2 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:17:30 PM 26 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:17:30 PM 10 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:17:30 PM 26 1362.00 TQEX
GENMAB A/S 26-Mar-25 4:18:05 PM 33 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:18:05 PM 47 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 16 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 27 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 20 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 39 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 12 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 14 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 50 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 8 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:18:25 PM 69 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:18:25 PM 28 1360.00 CEUX

56

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:18:26 PM 23 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:18:26 PM 24 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:19:33 PM 25 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:19:52 PM 9 1359.50 CEUX
GENMAB A/S 26-Mar-25 4:19:52 PM 14 1359.50 CEUX
GENMAB A/S 26-Mar-25 4:20:05 PM 48 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:05 PM 3 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:05 PM 43 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:35 PM 2 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:35 PM 48 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:35 PM 8 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:20:50 PM 1 1359.00 XCSE
GENMAB A/S 26-Mar-25 4:21:25 PM 3 1359.50 AQEU
GENMAB A/S 26-Mar-25 4:21:30 PM 7 1359.50 AQEU
GENMAB A/S 26-Mar-25 4:22:16 PM 41 1360.50 TQEX
GENMAB A/S 26-Mar-25 4:22:40 PM 71 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:22:40 PM 72 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:22:41 PM 26 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:22:41 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:22:55 PM 36 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:22:55 PM 36 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:22:55 PM 10 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:22:56 PM 50 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:23:11 PM 4 1360.50 TQEX
GENMAB A/S 26-Mar-25 4:23:55 PM 23 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:23:55 PM 10 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:23:56 PM 2 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:23:56 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:23:56 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:24:32 PM 9 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:24:32 PM 85 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:24:38 PM 5 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:24:57 PM 74 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:24:57 PM 36 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:24:57 PM 27 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:24:57 PM 1 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:24:57 PM 1 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:24:57 PM 27 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:25:04 PM 7 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:25:04 PM 17 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:25:09 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:25:09 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:25:09 PM 32 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:25:09 PM 73 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:25:09 PM 10 1361.50 AQEU

57

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:25:09 PM 15 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:25:39 PM 14 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:25:39 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:25:40 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:26:25 PM 7 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:26:25 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:26:25 PM 35 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:26:25 PM 32 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:27:21 PM 72 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:27:32 PM 10 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:27:34 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 28 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 48 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 8 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 3 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 16 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 50 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 1 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:27:34 PM 50 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:27:34 PM 21 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:27:34 PM 72 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:27:34 PM 2 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:27:34 PM 4 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:27:34 PM 23 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:27:34 PM 2 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:27:34 PM 13 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:27:34 PM 27 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:27:58 PM 30 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:58 PM 43 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:27:58 PM 8 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:28:00 PM 7 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:28:00 PM 19 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:28:26 PM 44 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:28:32 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 10 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 39 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 10 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 24 1359.00 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 12 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 48 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 12 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 12 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 45 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:04 PM 39 1359.50 CEUX
GENMAB A/S 26-Mar-25 4:29:04 PM 1 1358.50 CEUX

58

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:29:05 PM 16 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:05 PM 12 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:05 PM 45 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:05 PM 9 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:05 PM 12 1359.50 XCSE
GENMAB A/S 26-Mar-25 4:29:07 PM 18 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:29:07 PM 53 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:29:26 PM 2 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 6 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 2 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 14 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:06 PM 48 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 8 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 2 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 36 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 1 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 50 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 34 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 1 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 1 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 40 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 8 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:07 PM 38 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:30:08 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:08 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:08 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 37 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 35 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 2 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:23 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:25 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:25 PM 11 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:35 PM 11 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:35 PM 12 1360.50 XCSE

59

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:30:45 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:45 PM 11 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:30:45 PM 36 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:30:59 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:30:59 PM 70 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:31:05 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:31:05 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:31:05 PM 25 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:31:05 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:31:08 PM 25 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:31:11 PM 16 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:31:37 PM 15 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:31:44 PM 1 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:31:44 PM 5 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:32:24 PM 38 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:32:24 PM 1 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:32:25 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:33:23 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 46 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 34 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:23 PM 4 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:24 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:24 PM 23 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:24 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:24 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:25 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:33:25 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:34:08 PM 9 1362.00 TQEX
GENMAB A/S 26-Mar-25 4:34:08 PM 25 1362.00 TQEX
GENMAB A/S 26-Mar-25 4:34:14 PM 32 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:34:14 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:34:14 PM 34 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:36:16 PM 75 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:36:16 PM 28 1362.50 TQEX
GENMAB A/S 26-Mar-25 4:36:16 PM 33 1362.50 AQEU
GENMAB A/S 26-Mar-25 4:36:26 PM 22 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:26 PM 1 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:26 PM 48 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:26 PM 23 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:27 PM 23 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:27 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:27 PM 12 1362.50 XCSE

60

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:36:27 PM 48 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:29 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:29 PM 16 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:29 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:31 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:31 PM 13 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:31 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:32 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:32 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:32 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:32 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 35 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 48 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 7 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 30 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:36 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 31 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 41 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 40 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 3 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:37 PM 30 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:38 PM 45 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:38 PM 11 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:38 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:36:38 PM 26 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:05 PM 12 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:05 PM 9 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:05 PM 10 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:05 PM 30 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:05 PM 26 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:37:18 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:37:18 PM 10 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:37:18 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:37:25 PM 10 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:37:26 PM 22 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:37:27 PM 53 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:37:27 PM 28 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:37:27 PM 28 1362.00 CEUX

61

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:38:12 PM 30 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:38:26 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:38:26 PM 43 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:38:29 PM 22 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:38:54 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:38:54 PM 9 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:39:09 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:39:18 PM 12 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:39:24 PM 11 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:39:24 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:39:25 PM 74 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:39:25 PM 75 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:39:26 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:39:26 PM 27 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:39:26 PM 38 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:39:26 PM 11 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:40:27 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 7 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 23 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 42 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 3 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 39 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:40:27 PM 38 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:40:27 PM 27 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:40:28 PM 25 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:40:28 PM 49 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:41:11 PM 1 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:11 PM 27 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:22 PM 17 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:41:25 PM 22 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:41:25 PM 26 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:41:35 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 47 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 1 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 25 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:35 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:36 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:36 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:36 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:36 PM 11 1361.50 XCSE

62

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:41:36 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:37 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:37 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:40 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:40 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:41 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:42 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:42 PM 24 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:42 PM 48 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:42 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:44 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:41:57 PM 39 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:42:25 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:42:35 PM 20 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:43:26 PM 41 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:43:26 PM 2 1362.00 XCSE
GENMAB A/S 26-Mar-25 4:43:26 PM 19 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:44:27 PM 7 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:44:29 PM 18 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:44:44 PM 9 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:45:04 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:45:04 PM 12 1362.00 TQEX
GENMAB A/S 26-Mar-25 4:45:19 PM 26 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:46:35 PM 28 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:46:35 PM 46 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:46:35 PM 1 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:46:35 PM 70 1362.50 XCSE
GENMAB A/S 26-Mar-25 4:46:35 PM 72 1362.50 CEUX
GENMAB A/S 26-Mar-25 4:46:35 PM 38 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:46:35 PM 3 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 12 1362.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 8 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 15 1362.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 6 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 23 1362.50 TQEX
GENMAB A/S 26-Mar-25 4:46:35 PM 2 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:46:35 PM 22 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:46:36 PM 2 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:46:38 PM 29 1362.00 CEUX
GENMAB A/S 26-Mar-25 4:47:16 PM 46 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:47:36 PM 2 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:47:36 PM 12 1362.00 AQEU

63

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:47:36 PM 2 1362.00 AQEU
GENMAB A/S 26-Mar-25 4:47:40 PM 4 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:47:40 PM 5 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:47:41 PM 23 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:47:41 PM 28 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:47:41 PM 5 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:47:41 PM 5 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:48:04 PM 33 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:04 PM 38 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:48:04 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:04 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:04 PM 12 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:04 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:04 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:05 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:05 PM 8 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:09 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:09 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:09 PM 11 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:09 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:09 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:27 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 21 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:27 PM 12 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:27 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:27 PM 7 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:27 PM 2 1361.50 TQEX
GENMAB A/S 26-Mar-25 4:48:27 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:27 PM 2 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:27 PM 11 1361.50 AQEU
GENMAB A/S 26-Mar-25 4:48:29 PM 12 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:29 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:36 PM 5 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:48:37 PM 4 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:48:43 PM 2 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:43 PM 10 1361.50 XCSE
GENMAB A/S 26-Mar-25 4:48:43 PM 4 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:48:43 PM 92 1361.50 CEUX
GENMAB A/S 26-Mar-25 4:48:43 PM 9 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:48:43 PM 16 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:48:44 PM 9 1361.00 XCSE

64

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:48:44 PM 42 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 34 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 6 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 39 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 29 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 4 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 5 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:48:44 PM 38 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:44 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:44 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:44 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:44 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 10 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 2 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 12 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 38 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:45 PM 12 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:48:46 PM 41 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:49:05 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:49:05 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:49:05 PM 38 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:49:11 PM 61 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:49:11 PM 8 1360.50 TQEX
GENMAB A/S 26-Mar-25 4:49:11 PM 25 1360.50 TQEX
GENMAB A/S 26-Mar-25 4:49:25 PM 57 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:49:40 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:49:40 PM 11 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:49:41 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:49:41 PM 10 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:50:01 PM 10 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:01 PM 5 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:01 PM 5 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:01 PM 2 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:01 PM 2 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:02 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:02 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 4 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 1 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 3 1360.00 XCSE

65

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:50:11 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:11 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:11 PM 9 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:11 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:12 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:12 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:12 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:12 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:12 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:12 PM 9 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:12 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:12 PM 5 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:13 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:15 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:15 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:17 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:17 PM 39 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:18 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:18 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:19 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:19 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:19 PM 39 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:20 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:20 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:20 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:20 PM 4 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:20 PM 5 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:21 PM 2 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:22 PM 10 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:22 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:22 PM 11 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:23 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:23 PM 12 1360.00 XCSE
GENMAB A/S 26-Mar-25 4:50:23 PM 10 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:23 PM 5 1360.00 CEUX
GENMAB A/S 26-Mar-25 4:50:23 PM 8 1360.00 TQEX
GENMAB A/S 26-Mar-25 4:50:23 PM 12 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:23 PM 7 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:23 PM 2 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:50:23 PM 2 1360.00 AQEU
GENMAB A/S 26-Mar-25 4:51:03 PM 62 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:51:03 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:51:07 PM 74 1361.00 CEUX

66

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:51:24 PM 27 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:51:25 PM 55 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:51:41 PM 70 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:51:41 PM 71 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:51:41 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:51:41 PM 29 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:52:00 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 3 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 23 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 6 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 2 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:00 PM 11 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:52:00 PM 12 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:52:03 PM 9 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:06 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:06 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:06 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:52:06 PM 2 1361.00 AQEU
GENMAB A/S 26-Mar-25 4:52:13 PM 4 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:52:13 PM 2 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:52:27 PM 26 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:53:11 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 3 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 94 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 3 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:11 PM 6 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:12 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:12 PM 10 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:12 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:12 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:12 PM 48 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:42 PM 10 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:53:55 PM 22 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:53:57 PM 12 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:53:57 PM 24 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:53:57 PM 11 1360.50 XCSE
GENMAB A/S 26-Mar-25 4:53:57 PM 5 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:53:57 PM 5 1360.50 CEUX
GENMAB A/S 26-Mar-25 4:53:57 PM 2 1360.50 TQEX
GENMAB A/S 26-Mar-25 4:53:57 PM 20 1360.50 AQEU

67

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 26-Mar-25 4:53:57 PM 2 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:53:58 PM 12 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:58 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:58 PM 11 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:53:58 PM 35 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:53:58 PM 5 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:53:58 PM 4 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:53:58 PM 15 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:53:58 PM 4 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:54:05 PM 75 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:54:05 PM 75 1361.00 CEUX
GENMAB A/S 26-Mar-25 4:54:10 PM 42 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:54:10 PM 33 1361.00 TQEX
GENMAB A/S 26-Mar-25 4:54:29 PM 10 1360.50 AQEU
GENMAB A/S 26-Mar-25 4:54:32 PM 75 1361.00 XCSE
GENMAB A/S 26-Mar-25 4:54:37 PM 25 1361.50 CEUX
GENMAB A/S 27-Mar-25 9:42:33 AM 49 1344.50 XCSE
GENMAB A/S 27-Mar-25 9:43:04 AM 69 1345.00 TQEX
GENMAB A/S 27-Mar-25 9:43:31 AM 24 1344.50 XCSE
GENMAB A/S 27-Mar-25 9:43:32 AM 70 1344.00 TQEX
GENMAB A/S 27-Mar-25 9:43:36 AM 70 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:43:36 AM 64 1343.50 CEUX
GENMAB A/S 27-Mar-25 9:43:36 AM 65 1343.50 AQEU
GENMAB A/S 27-Mar-25 9:44:02 AM 3 1344.50 XCSE
GENMAB A/S 27-Mar-25 9:44:02 AM 18 1344.50 XCSE
GENMAB A/S 27-Mar-25 9:44:02 AM 11 1344.50 XCSE
GENMAB A/S 27-Mar-25 9:44:02 AM 23 1344.50 CEUX
GENMAB A/S 27-Mar-25 9:44:02 AM 22 1344.50 TQEX
GENMAB A/S 27-Mar-25 9:44:02 AM 24 1344.50 AQEU
GENMAB A/S 27-Mar-25 9:44:39 AM 8 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:45:08 AM 16 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:45:08 AM 51 1343.50 CEUX
GENMAB A/S 27-Mar-25 9:45:08 AM 14 1343.50 TQEX
GENMAB A/S 27-Mar-25 9:45:08 AM 45 1343.50 AQEU
GENMAB A/S 27-Mar-25 9:45:32 AM 31 1342.50 XCSE
GENMAB A/S 27-Mar-25 9:45:32 AM 75 1342.50 AQEU
GENMAB A/S 27-Mar-25 9:45:51 AM 28 1342.00 CEUX
GENMAB A/S 27-Mar-25 9:45:51 AM 44 1342.00 CEUX
GENMAB A/S 27-Mar-25 9:48:05 AM 2 1342.00 CEUX
GENMAB A/S 27-Mar-25 9:49:12 AM 12 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:49:20 AM 46 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:51:12 AM 57 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:51:12 AM 20 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:52:29 AM 75 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:52:29 AM 35 1343.50 TQEX

68

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 9:53:16 AM 74 1343.50 XCSE
GENMAB A/S 27-Mar-25 9:53:16 AM 11 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:53:16 AM 18 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:54:42 AM 46 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:55:22 AM 10 1343.00 CEUX
GENMAB A/S 27-Mar-25 9:59:07 AM 32 1345.50 CEUX
GENMAB A/S 27-Mar-25 9:59:56 AM 44 1345.00 CEUX
GENMAB A/S 27-Mar-25 9:59:56 AM 29 1345.00 CEUX
GENMAB A/S 27-Mar-25 10:01:04 AM 73 1344.50 XCSE
GENMAB A/S 27-Mar-25 10:01:04 AM 1 1344.00 CEUX
GENMAB A/S 27-Mar-25 10:04:06 AM 13 1344.50 CEUX
GENMAB A/S 27-Mar-25 10:05:26 AM 74 1344.00 CEUX
GENMAB A/S 27-Mar-25 10:06:35 AM 1 1345.50 CEUX
GENMAB A/S 27-Mar-25 10:07:01 AM 66 1345.50 XCSE
GENMAB A/S 27-Mar-25 10:07:01 AM 9 1345.50 XCSE
GENMAB A/S 27-Mar-25 10:09:29 AM 33 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:29 AM 2 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:29 AM 43 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:29 AM 9 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:29 AM 9 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:41 AM 17 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:41 AM 16 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:41 AM 57 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:09:41 AM 8 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:10:00 AM 26 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:10:00 AM 12 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:10:00 AM 6 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:10:01 AM 10 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:10:45 AM 72 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:10:45 AM 73 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:12:02 AM 15 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:12:02 AM 3 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:12:02 AM 75 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:12:03 AM 16 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:12:10 AM 10 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:12:10 AM 4 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:12:10 AM 9 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:12:10 AM 10 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:12:13 AM 15 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:14:00 AM 16 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:14:00 AM 15 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:14:00 AM 38 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:14:00 AM 4 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:14:00 AM 21 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:14:00 AM 36 1347.00 CEUX

69

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 10:15:01 AM 51 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:01 AM 36 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:01 AM 72 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:01 AM 11 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:01 AM 6 1346.00 CEUX
GENMAB A/S 27-Mar-25 10:15:01 AM 36 1346.50 CEUX
GENMAB A/S 27-Mar-25 10:15:01 AM 71 1346.00 CEUX
GENMAB A/S 27-Mar-25 10:15:02 AM 30 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:02 AM 11 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:02 AM 49 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:02 AM 8 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:15:04 AM 15 1346.00 XCSE
GENMAB A/S 27-Mar-25 10:15:04 AM 7 1346.00 XCSE
GENMAB A/S 27-Mar-25 10:15:10 AM 19 1345.50 XCSE
GENMAB A/S 27-Mar-25 10:15:10 AM 59 1345.50 XCSE
GENMAB A/S 27-Mar-25 10:15:10 AM 20 1345.50 CEUX
GENMAB A/S 27-Mar-25 10:15:19 AM 36 1345.50 CEUX
GENMAB A/S 27-Mar-25 10:17:03 AM 7 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:20:08 AM 15 1347.00 TQEX
GENMAB A/S 27-Mar-25 10:20:28 AM 7 1347.00 TQEX
GENMAB A/S 27-Mar-25 10:21:45 AM 11 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:21:45 AM 5 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:21:45 AM 9 1347.00 XCSE
GENMAB A/S 27-Mar-25 10:21:45 AM 36 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:21:45 AM 5 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:21:46 AM 13 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:21:46 AM 30 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:21:46 AM 20 1347.00 CEUX
GENMAB A/S 27-Mar-25 10:22:53 AM 73 1346.50 XCSE
GENMAB A/S 27-Mar-25 10:22:53 AM 6 1346.50 CEUX
GENMAB A/S 27-Mar-25 10:24:43 AM 5 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:24:43 AM 5 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:24:43 AM 18 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:24:43 AM 5 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:25:04 AM 11 1347.50 CEUX
GENMAB A/S 27-Mar-25 10:27:16 AM 19 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:27:16 AM 12 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:27:16 AM 33 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:27:16 AM 1 1349.50 CEUX
GENMAB A/S 27-Mar-25 10:27:16 AM 12 1349.50 CEUX
GENMAB A/S 27-Mar-25 10:29:47 AM 98 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:29:47 AM 46 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:29:47 AM 39 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:29:47 AM 13 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:29:47 AM 7 1350.00 CEUX

70

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 10:29:47 AM 12 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:30:18 AM 37 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 4 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 43 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 9 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 43 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 18 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:30:18 AM 36 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:31:53 AM 11 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:31:53 AM 3 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:31:53 AM 9 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:32:03 AM 3 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:32:24 AM 10 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:32:24 AM 4 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:32:24 AM 6 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:32:28 AM 26 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:32:28 AM 11 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:33:06 AM 34 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:34:10 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:10 AM 21 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:10 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:11 AM 28 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:12 AM 77 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:34:12 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:12 AM 57 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:34:12 AM 10 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:34:12 AM 42 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:34:13 AM 22 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:34:13 AM 16 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:34:21 AM 15 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:35:03 AM 11 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:35:07 AM 28 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:35:24 AM 16 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:35:26 AM 36 1351.50 TQEX
GENMAB A/S 27-Mar-25 10:35:27 AM 64 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:35:27 AM 10 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:38:23 AM 72 1350.50 XCSE
GENMAB A/S 27-Mar-25 10:38:23 AM 72 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:38:23 AM 31 1350.50 CEUX
GENMAB A/S 27-Mar-25 10:38:23 AM 1 1350.50 CEUX
GENMAB A/S 27-Mar-25 10:38:23 AM 36 1350.50 CEUX
GENMAB A/S 27-Mar-25 10:38:23 AM 37 1350.50 TQEX
GENMAB A/S 27-Mar-25 10:38:25 AM 54 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:38:25 AM 19 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:38:25 AM 25 1350.00 XCSE

71

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 10:38:25 AM 4 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:38:25 AM 5 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:38:25 AM 12 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:38:25 AM 4 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:38:25 AM 23 1349.50 TQEX
GENMAB A/S 27-Mar-25 10:38:52 AM 10 1349.50 XCSE
GENMAB A/S 27-Mar-25 10:41:39 AM 29 1350.00 TQEX
GENMAB A/S 27-Mar-25 10:42:14 AM 75 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:42:14 AM 28 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:14 AM 46 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:14 AM 25 1350.00 AQEU
GENMAB A/S 27-Mar-25 10:42:16 AM 10 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:42:16 AM 15 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:16 AM 13 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:16 AM 19 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:18 AM 1 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:42:24 AM 12 1350.00 CEUX
GENMAB A/S 27-Mar-25 10:45:19 AM 8 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:45:59 AM 66 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:45:59 AM 13 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:45:59 AM 48 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:45:59 AM 4 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 72 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 5 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 30 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 5 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 34 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 39 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:45:59 AM 31 1351.00 TQEX
GENMAB A/S 27-Mar-25 10:45:59 AM 22 1351.00 AQEU
GENMAB A/S 27-Mar-25 10:46:00 AM 36 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:00 AM 5 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:00 AM 4 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:00 AM 4 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:01 AM 31 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:01 AM 31 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:06 AM 22 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 12 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 5 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 4 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 5 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 14 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 17 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:07 AM 2 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:09 AM 3 1351.00 CEUX

72

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 10:46:14 AM 13 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:46:42 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:46:42 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:46:42 AM 10 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:46:42 AM 5 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:46:42 AM 4 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:46:42 AM 4 1352.00 CEUX
GENMAB A/S 27-Mar-25 10:49:33 AM 50 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:50:21 AM 30 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:50:21 AM 19 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:50:21 AM 13 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:40 AM 18 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:40 AM 2 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:41 AM 25 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:43 AM 15 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:44 AM 22 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:45 AM 4 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:51:48 AM 14 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:55:17 AM 76 1351.00 XCSE
GENMAB A/S 27-Mar-25 10:55:17 AM 77 1350.00 XCSE
GENMAB A/S 27-Mar-25 10:55:17 AM 77 1351.00 CEUX
GENMAB A/S 27-Mar-25 10:55:17 AM 30 1350.00 TQEX
GENMAB A/S 27-Mar-25 10:55:17 AM 23 1351.00 TQEX
GENMAB A/S 27-Mar-25 10:55:40 AM 50 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:55:40 AM 5 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:55:40 AM 73 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:55:40 AM 18 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:55:40 AM 25 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:55:40 AM 19 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:56:11 AM 22 1352.00 AQEU
GENMAB A/S 27-Mar-25 10:56:12 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 10 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 20 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 50 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 20 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 10 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:12 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 78 1351.50 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 8 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 43 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 26 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 5 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 8 1352.00 XCSE

73

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 10:56:26 AM 8 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:26 AM 15 1351.50 CEUX
GENMAB A/S 27-Mar-25 10:56:27 AM 10 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:27 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:56:27 AM 9 1352.00 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 30 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 6 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 2 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 11 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:00 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 43 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 2 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:01 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:02 AM 43 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:02 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:02 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 10:58:04 AM 14 1352.50 CEUX
GENMAB A/S 27-Mar-25 10:58:04 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 10:58:04 AM 10 1352.50 CEUX
GENMAB A/S 27-Mar-25 10:59:52 AM 15 1352.50 CEUX
GENMAB A/S 27-Mar-25 10:59:53 AM 14 1352.50 CEUX
GENMAB A/S 27-Mar-25 10:59:55 AM 2 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:00:13 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:00:13 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:00:13 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:00:21 AM 10 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:01:06 AM 11 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:01:51 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:01:51 AM 11 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:01:57 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:14 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:14 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:14 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:14 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:15 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:15 AM 10 1352.50 XCSE

74

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:02:15 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:36 AM 11 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:50 AM 45 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:50 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:51 AM 45 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:51 AM 45 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:51 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:02:51 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:51 AM 4 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:51 AM 4 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:51 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:51 AM 4 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:02:56 AM 54 1352.00 XCSE
GENMAB A/S 27-Mar-25 11:02:56 AM 44 1352.00 XCSE
GENMAB A/S 27-Mar-25 11:02:56 AM 7 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:02:56 AM 73 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:02:56 AM 29 1352.00 TQEX
GENMAB A/S 27-Mar-25 11:03:27 AM 39 1352.00 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 2 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 29 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 2 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:38 AM 36 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:39 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:39 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:39 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:39 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:40 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:40 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:40 AM 8 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:43 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:44 AM 4 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:44 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:44 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:46 AM 9 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:46 AM 10 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:04:46 AM 3 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:05:42 AM 30 1352.00 TQEX
GENMAB A/S 27-Mar-25 11:05:45 AM 41 1352.00 XCSE
GENMAB A/S 27-Mar-25 11:05:45 AM 17 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:05:45 AM 23 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:05:45 AM 26 1352.00 AQEU
GENMAB A/S 27-Mar-25 11:07:10 AM 5 1352.00 CEUX

75

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:07:10 AM 72 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:10 AM 5 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:10 AM 4 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:10 AM 32 1352.00 TQEX
GENMAB A/S 27-Mar-25 11:07:11 AM 32 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:11 AM 29 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:11 AM 19 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:13 AM 36 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:07:13 AM 22 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 24 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 4 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 11 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 5 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 11 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:53 AM 13 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:55 AM 30 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:55 AM 10 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:55 AM 9 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:55 AM 10 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:55 AM 8 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:55 AM 8 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 7 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 32 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 10 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 10 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 10 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 11 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 9 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 3 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 8 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 17 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 43 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 6 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:56 AM 30 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:09:58 AM 40 1353.00 XCSE
GENMAB A/S 27-Mar-25 11:09:58 AM 74 1352.50 XCSE
GENMAB A/S 27-Mar-25 11:09:58 AM 20 1352.50 CEUX
GENMAB A/S 27-Mar-25 11:09:58 AM 74 1353.00 CEUX
GENMAB A/S 27-Mar-25 11:09:58 AM 22 1353.00 TQEX
GENMAB A/S 27-Mar-25 11:10:14 AM 75 1351.50 XCSE
GENMAB A/S 27-Mar-25 11:10:14 AM 73 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:10:14 AM 78 1351.00 CEUX
GENMAB A/S 27-Mar-25 11:10:14 AM 24 1351.00 TQEX
GENMAB A/S 27-Mar-25 11:10:14 AM 26 1352.00 TQEX
GENMAB A/S 27-Mar-25 11:10:14 AM 24 1352.00 AQEU

76

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:10:42 AM 38 1350.50 XCSE
GENMAB A/S 27-Mar-25 11:10:42 AM 73 1350.50 XCSE
GENMAB A/S 27-Mar-25 11:12:17 AM 2 1352.00 AQEU
GENMAB A/S 27-Mar-25 11:13:07 AM 37 1351.50 XCSE
GENMAB A/S 27-Mar-25 11:13:16 AM 38 1351.50 XCSE
GENMAB A/S 27-Mar-25 11:13:16 AM 75 1351.50 CEUX
GENMAB A/S 27-Mar-25 11:13:16 AM 36 1352.00 CEUX
GENMAB A/S 27-Mar-25 11:13:16 AM 32 1352.00 AQEU
GENMAB A/S 27-Mar-25 11:13:34 AM 26 1351.00 TQEX
GENMAB A/S 27-Mar-25 11:13:35 AM 14 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:13:35 AM 33 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:13:35 AM 8 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:13:35 AM 43 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:13:35 AM 37 1350.50 CEUX
GENMAB A/S 27-Mar-25 11:13:35 AM 36 1350.50 CEUX
GENMAB A/S 27-Mar-25 11:15:11 AM 76 1350.50 XCSE
GENMAB A/S 27-Mar-25 11:15:11 AM 11 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:11 AM 57 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:11 AM 30 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:11 AM 1 1350.50 CEUX
GENMAB A/S 27-Mar-25 11:15:12 AM 10 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:12 AM 23 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:12 AM 8 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:12 AM 10 1351.00 XCSE
GENMAB A/S 27-Mar-25 11:15:19 AM 75 1350.50 XCSE
GENMAB A/S 27-Mar-25 11:15:26 AM 43 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:15:26 AM 77 1357.00 XCSE
GENMAB A/S 27-Mar-25 11:15:26 AM 23 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:15:26 AM 11 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:15:26 AM 76 1356.00 CEUX
GENMAB A/S 27-Mar-25 11:15:31 AM 43 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:15:31 AM 22 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:15:31 AM 33 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:15:31 AM 36 1356.50 CEUX
GENMAB A/S 27-Mar-25 11:15:41 AM 20 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:15:41 AM 74 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:15:41 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:15:41 AM 22 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:15:41 AM 76 1355.50 TQEX
GENMAB A/S 27-Mar-25 11:15:41 AM 74 1355.50 AQEU
GENMAB A/S 27-Mar-25 11:16:06 AM 74 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:16:06 AM 12 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:16:06 AM 71 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:16:06 AM 36 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:16:06 AM 73 1355.00 CEUX

77

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:16:06 AM 68 1354.50 TQEX
GENMAB A/S 27-Mar-25 11:16:06 AM 71 1354.50 AQEU
GENMAB A/S 27-Mar-25 11:16:07 AM 36 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:16:48 AM 19 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:16:48 AM 28 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:16:48 AM 26 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:16:48 AM 2 1354.50 TQEX
GENMAB A/S 27-Mar-25 11:16:51 AM 16 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:16:51 AM 8 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:17:57 AM 27 1354.00 AQEU
GENMAB A/S 27-Mar-25 11:18:00 AM 30 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:18:00 AM 17 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:18:00 AM 36 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:00 AM 22 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:00 AM 18 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:00 AM 63 1354.00 TQEX
GENMAB A/S 27-Mar-25 11:18:00 AM 28 1354.00 AQEU
GENMAB A/S 27-Mar-25 11:18:00 AM 14 1354.00 AQEU
GENMAB A/S 27-Mar-25 11:18:02 AM 31 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:04 AM 36 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:10 AM 24 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:18:13 AM 58 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:18:13 AM 30 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:18:13 AM 17 1353.50 CEUX
GENMAB A/S 27-Mar-25 11:18:13 AM 60 1353.50 CEUX
GENMAB A/S 27-Mar-25 11:18:52 AM 41 1353.00 AQEU
GENMAB A/S 27-Mar-25 11:20:00 AM 11 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:00 AM 87 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:01 AM 11 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:01 AM 2 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:01 AM 1 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:01 AM 3 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:01 AM 1 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:09 AM 46 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:09 AM 23 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:09 AM 7 1353.50 CEUX
GENMAB A/S 27-Mar-25 11:20:09 AM 14 1353.50 CEUX
GENMAB A/S 27-Mar-25 11:20:09 AM 15 1353.50 CEUX
GENMAB A/S 27-Mar-25 11:20:14 AM 17 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:38 AM 3 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:38 AM 19 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:20:38 AM 3 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:21:42 AM 2 1353.50 XCSE
GENMAB A/S 27-Mar-25 11:22:12 AM 12 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:22:12 AM 12 1354.00 CEUX

78

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:22:12 AM 24 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:22:12 AM 9 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:24:07 AM 17 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:24:10 AM 18 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:24:11 AM 30 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:24:11 AM 30 1354.00 XCSE
GENMAB A/S 27-Mar-25 11:24:11 AM 40 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:24:11 AM 2 1354.00 CEUX
GENMAB A/S 27-Mar-25 11:25:16 AM 32 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:16 AM 15 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:16 AM 15 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:16 AM 5 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:16 AM 31 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 25 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 8 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 1 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 8 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 8 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 48 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 14 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 43 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 3 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:17 AM 3 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:25:28 AM 20 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:33 AM 25 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:33 AM 38 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:33 AM 30 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:34 AM 30 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:34 AM 10 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:34 AM 8 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:34 AM 10 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:34 AM 30 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:35 AM 30 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:35 AM 8 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:25:36 AM 4 1354.50 XCSE
GENMAB A/S 27-Mar-25 11:28:06 AM 6 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 25 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 10 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 9 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 19 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 8 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:06 AM 10 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:28:27 AM 4 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:28:27 AM 15 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:28:27 AM 22 1355.00 CEUX

79

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:28:27 AM 6 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:28:27 AM 8 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:28:28 AM 32 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:29:16 AM 74 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:16 AM 60 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:29:16 AM 14 1355.00 AQEU
GENMAB A/S 27-Mar-25 11:29:17 AM 23 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:17 AM 44 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:17 AM 32 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:29:17 AM 35 1355.00 AQEU
GENMAB A/S 27-Mar-25 11:29:36 AM 22 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:36 AM 30 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:36 AM 21 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:29:36 AM 77 1354.50 CEUX
GENMAB A/S 27-Mar-25 11:33:32 AM 15 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:32 AM 4 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:32 AM 23 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:32 AM 9 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:32 AM 10 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:36 AM 14 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:33:54 AM 23 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:33:58 AM 17 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:33:58 AM 3 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:35:53 AM 30 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 74 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 6 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 68 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 4 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 26 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 24 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:35:53 AM 36 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:35:54 AM 23 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:36:13 AM 7 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:36:13 AM 47 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:36:13 AM 21 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:36:13 AM 75 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:36:13 AM 15 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:36:13 AM 24 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:36:36 AM 3 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:36:44 AM 2 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 30 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 34 1355.50 XCSE

80

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:37:17 AM 30 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 73 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:17 AM 38 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:18 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:30 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:30 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:30 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:30 AM 3 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:30 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:32 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:32 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:32 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:33 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:38 AM 19 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:39 AM 2 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:41 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:41 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:41 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:43 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:37:45 AM 46 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:39:58 AM 36 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:39:58 AM 25 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:40:00 AM 30 1355.00 AQEU
GENMAB A/S 27-Mar-25 11:40:28 AM 13 1355.00 AQEU
GENMAB A/S 27-Mar-25 11:43:11 AM 25 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:43:11 AM 44 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:43:11 AM 36 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:11 AM 11 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:11 AM 14 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:11 AM 30 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:43:11 AM 4 1355.00 AQEU
GENMAB A/S 27-Mar-25 11:43:51 AM 30 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:43:51 AM 43 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:43:51 AM 39 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:43:51 AM 17 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:51 AM 22 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:51 AM 14 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:51 AM 24 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:43:52 AM 3 1355.00 CEUX
GENMAB A/S 27-Mar-25 11:44:02 AM 50 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:44:03 AM 27 1355.00 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 8 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 27 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 13 1355.50 XCSE

81

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:44:53 AM 27 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 9 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 27 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 19 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 4 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:53 AM 28 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:44:53 AM 21 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:44:53 AM 4 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:44:57 AM 2 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:57 AM 93 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:44:58 AM 2 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:06 AM 45 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:06 AM 3 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:06 AM 28 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:07 AM 20 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:07 AM 62 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:45:29 AM 1 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:45:29 AM 12 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:45:29 AM 5 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:45:59 AM 15 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:45:59 AM 36 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:45:59 AM 3 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:46:31 AM 17 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:46:31 AM 10 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:46:31 AM 23 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:46:37 AM 10 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:46:37 AM 9 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:46:38 AM 8 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:47:07 AM 78 1356.00 XCSE
GENMAB A/S 27-Mar-25 11:48:09 AM 4 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:48:09 AM 43 1355.50 XCSE
GENMAB A/S 27-Mar-25 11:48:09 AM 36 1356.00 CEUX
GENMAB A/S 27-Mar-25 11:48:09 AM 5 1356.00 CEUX
GENMAB A/S 27-Mar-25 11:48:09 AM 77 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:48:09 AM 20 1355.50 CEUX
GENMAB A/S 27-Mar-25 11:48:09 AM 25 1355.00 TQEX
GENMAB A/S 27-Mar-25 11:49:37 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 43 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 9 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 9 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 9 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 9 1356.50 XCSE

82

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:49:37 AM 43 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:37 AM 28 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 10 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 10 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 12 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 10 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:38 AM 41 1356.00 AQEU
GENMAB A/S 27-Mar-25 11:49:40 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:40 AM 9 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:40 AM 8 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:45 AM 9 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:45 AM 13 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:49:48 AM 10 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:50:43 AM 10 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:50:43 AM 1 1356.50 XCSE
GENMAB A/S 27-Mar-25 11:51:24 AM 96 1357.00 XCSE
GENMAB A/S 27-Mar-25 11:51:24 AM 2 1357.00 XCSE
GENMAB A/S 27-Mar-25 11:51:27 AM 3 1357.50 XCSE
GENMAB A/S 27-Mar-25 11:51:27 AM 18 1357.50 XCSE
GENMAB A/S 27-Mar-25 11:52:04 AM 7 1357.50 CEUX
GENMAB A/S 27-Mar-25 11:52:30 AM 2 1358.00 XCSE
GENMAB A/S 27-Mar-25 11:52:30 AM 50 1358.00 XCSE
GENMAB A/S 27-Mar-25 11:52:36 AM 2 1358.00 XCSE
GENMAB A/S 27-Mar-25 11:52:51 AM 3 1358.00 XCSE
GENMAB A/S 27-Mar-25 11:53:02 AM 3 1358.00 XCSE
GENMAB A/S 27-Mar-25 11:53:03 AM 13 1358.00 CEUX
GENMAB A/S 27-Mar-25 11:53:03 AM 15 1358.00 CEUX
GENMAB A/S 27-Mar-25 11:53:31 AM 3 1358.50 CEUX
GENMAB A/S 27-Mar-25 11:53:51 AM 12 1358.50 CEUX
GENMAB A/S 27-Mar-25 11:55:09 AM 73 1358.50 XCSE
GENMAB A/S 27-Mar-25 11:55:09 AM 32 1358.50 CEUX
GENMAB A/S 27-Mar-25 11:55:09 AM 43 1358.50 CEUX
GENMAB A/S 27-Mar-25 11:55:09 AM 34 1358.50 CEUX
GENMAB A/S 27-Mar-25 11:55:42 AM 9 1360.50 XCSE
GENMAB A/S 27-Mar-25 11:55:42 AM 8 1360.50 XCSE
GENMAB A/S 27-Mar-25 11:55:42 AM 10 1360.50 XCSE
GENMAB A/S 27-Mar-25 11:55:42 AM 72 1360.50 CEUX
GENMAB A/S 27-Mar-25 11:55:43 AM 75 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:43 AM 78 1360.00 TQEX
GENMAB A/S 27-Mar-25 11:55:43 AM 44 1360.00 AQEU
GENMAB A/S 27-Mar-25 11:55:45 AM 70 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:45 AM 15 1360.00 XCSE

83

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:55:45 AM 13 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 7 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 11 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 10 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 25 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 36 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 10 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:46 AM 11 1359.50 CEUX
GENMAB A/S 27-Mar-25 11:55:47 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:47 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:47 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:47 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:47 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:47 AM 10 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:48 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:51 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 4 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 43 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 24 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:58 AM 66 1359.50 CEUX
GENMAB A/S 27-Mar-25 11:55:59 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:59 AM 10 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:59 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:59 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:59 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:55:59 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:00 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:00 AM 9 1360.00 XCSE

84

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:56:00 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:01 AM 10 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:01 AM 9 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:01 AM 8 1360.00 XCSE
GENMAB A/S 27-Mar-25 11:56:56 AM 29 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:56:56 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:56:56 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:56:56 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:56:56 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:57:11 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:57:44 AM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:57:51 AM 3 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 7 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 45 1360.50 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:06 AM 34 1360.50 CEUX
GENMAB A/S 27-Mar-25 11:58:06 AM 43 1360.50 CEUX
GENMAB A/S 27-Mar-25 11:58:07 AM 30 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 39 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 30 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 31 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 29 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:07 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 42 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 30 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 17 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:08 AM 30 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 8 1361.00 XCSE

85

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:58:09 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 14 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 27 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 16 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 26 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:09 AM 9 1360.50 CEUX
GENMAB A/S 27-Mar-25 11:58:09 AM 68 1360.50 CEUX
GENMAB A/S 27-Mar-25 11:58:09 AM 11 1360.00 AQEU
GENMAB A/S 27-Mar-25 11:58:10 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 26 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:10 AM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:13 AM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:13 AM 23 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:18 AM 23 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:19 AM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 25 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:22 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 14 1361.50 XCSE

86

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 11:58:23 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:23 AM 1 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:24 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:24 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:58:27 AM 71 1361.00 TQEX
GENMAB A/S 27-Mar-25 11:58:27 AM 54 1361.00 AQEU
GENMAB A/S 27-Mar-25 11:59:47 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 33 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 31 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 16 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 13 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 7 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:47 AM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:48 AM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 11:59:48 AM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:13 PM 22 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:13 PM 43 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:24 PM 76 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:24 PM 24 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:24 PM 78 1361.50 CEUX
GENMAB A/S 27-Mar-25 12:00:43 PM 2 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:00:51 PM 3 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:17 PM 69 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:17 PM 31 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 39 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:18 PM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:19 PM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:19 PM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:19 PM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:19 PM 10 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 39 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 39 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 8 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 9 1361.50 XCSE
GENMAB A/S 27-Mar-25 12:01:20 PM 9 1361.50 XCSE

87

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:01:20 PM 42 1361.00 AQEU
GENMAB A/S 27-Mar-25 12:01:28 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:01:28 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:01:36 PM 28 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:01:36 PM 5 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:02:06 PM 37 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:02:06 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:02:18 PM 54 1360.50 CEUX
GENMAB A/S 27-Mar-25 12:02:58 PM 78 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:02:58 PM 72 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:02:58 PM 60 1363.00 TQEX
GENMAB A/S 27-Mar-25 12:02:58 PM 39 1363.00 AQEU
GENMAB A/S 27-Mar-25 12:03:21 PM 75 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:03:21 PM 32 1363.50 CEUX
GENMAB A/S 27-Mar-25 12:03:23 PM 48 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:03:23 PM 33 1363.00 TQEX
GENMAB A/S 27-Mar-25 12:03:23 PM 18 1363.00 AQEU
GENMAB A/S 27-Mar-25 12:04:34 PM 10 1363.00 AQEU
GENMAB A/S 27-Mar-25 12:09:49 PM 62 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:09:50 PM 30 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:10:05 PM 14 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 33 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 34 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 15 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 13 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 43 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 16 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:20 PM 17 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:21 PM 9 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:21 PM 33 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:21 PM 98 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:21 PM 8 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:10:21 PM 8 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:11:06 PM 4 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:11:06 PM 12 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:11:06 PM 4 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:11:06 PM 8 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:11:06 PM 9 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:11:33 PM 74 1362.00 XCSE
GENMAB A/S 27-Mar-25 12:11:33 PM 72 1362.00 CEUX
GENMAB A/S 27-Mar-25 12:11:33 PM 58 1362.00 TQEX
GENMAB A/S 27-Mar-25 12:11:33 PM 12 1362.00 AQEU
GENMAB A/S 27-Mar-25 12:11:33 PM 3 1362.00 AQEU
GENMAB A/S 27-Mar-25 12:11:33 PM 21 1362.00 AQEU
GENMAB A/S 27-Mar-25 12:11:42 PM 47 1361.00 XCSE

88

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:11:42 PM 25 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:11:42 PM 22 1361.00 CEUX
GENMAB A/S 27-Mar-25 12:11:42 PM 30 1361.00 AQEU
GENMAB A/S 27-Mar-25 12:12:01 PM 33 1360.50 TQEX
GENMAB A/S 27-Mar-25 12:12:07 PM 27 1360.00 CEUX
GENMAB A/S 27-Mar-25 12:12:07 PM 15 1360.00 AQEU
GENMAB A/S 27-Mar-25 12:12:09 PM 9 1360.00 AQEU
GENMAB A/S 27-Mar-25 12:13:56 PM 4 1360.00 XCSE
GENMAB A/S 27-Mar-25 12:13:56 PM 23 1360.00 XCSE
GENMAB A/S 27-Mar-25 12:14:12 PM 74 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:14:12 PM 70 1359.50 CEUX
GENMAB A/S 27-Mar-25 12:14:12 PM 6 1359.50 CEUX
GENMAB A/S 27-Mar-25 12:14:12 PM 28 1359.50 TQEX
GENMAB A/S 27-Mar-25 12:15:40 PM 22 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:15:46 PM 9 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:15:46 PM 10 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:15:46 PM 9 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:16:45 PM 43 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:16:45 PM 6 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:17:40 PM 8 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:17:40 PM 2 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:17:46 PM 26 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:17:47 PM 3 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:18:08 PM 75 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:18:08 PM 8 1359.50 TQEX
GENMAB A/S 27-Mar-25 12:18:15 PM 76 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:18:15 PM 72 1358.50 CEUX
GENMAB A/S 27-Mar-25 12:18:15 PM 24 1358.50 AQEU
GENMAB A/S 27-Mar-25 12:18:15 PM 3 1358.50 AQEU
GENMAB A/S 27-Mar-25 12:19:27 PM 50 1357.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 9 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 43 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 15 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 2 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 10 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 13 1358.50 XCSE
GENMAB A/S 27-Mar-25 12:23:19 PM 7 1358.50 AQEU
GENMAB A/S 27-Mar-25 12:23:24 PM 75 1359.00 XCSE
GENMAB A/S 27-Mar-25 12:27:25 PM 43 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:27:25 PM 9 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:27:26 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:27:26 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:27:26 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:27:26 PM 1 1359.50 XCSE
GENMAB A/S 27-Mar-25 12:27:27 PM 72 1360.50 XCSE

89

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:27:27 PM 5 1361.00 CEUX
GENMAB A/S 27-Mar-25 12:27:27 PM 73 1360.50 CEUX
GENMAB A/S 27-Mar-25 12:27:27 PM 5 1361.00 CEUX
GENMAB A/S 27-Mar-25 12:27:27 PM 36 1361.00 CEUX
GENMAB A/S 27-Mar-25 12:27:27 PM 4 1361.00 CEUX
GENMAB A/S 27-Mar-25 12:27:27 PM 31 1360.50 TQEX
GENMAB A/S 27-Mar-25 12:30:24 PM 28 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:24 PM 12 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:24 PM 6 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:25 PM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:25 PM 14 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:25 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:25 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:26 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:26 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:26 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:27 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:29 PM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:29 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:29 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:31 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:32 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:32 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:32 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:32 PM 2 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:33 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:33 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:41 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:41 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:43 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:30:43 PM 9 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:31:17 PM 14 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:35 PM 43 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:35 PM 10 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:37 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:37 PM 13 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:41 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:32:42 PM 8 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:34:36 PM 20 1361.00 XCSE
GENMAB A/S 27-Mar-25 12:35:49 PM 76 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:49 PM 36 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:49 PM 72 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:49 PM 26 1363.00 TQEX
GENMAB A/S 27-Mar-25 12:35:49 PM 8 1363.00 TQEX
GENMAB A/S 27-Mar-25 12:35:49 PM 24 1363.00 AQEU

90

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:35:50 PM 41 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:50 PM 19 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:50 PM 38 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:50 PM 78 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 23 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:51 PM 19 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:51 PM 43 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:35:51 PM 5 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 12 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 4 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 5 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 5 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 36 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:35:51 PM 25 1362.50 TQEX
GENMAB A/S 27-Mar-25 12:35:53 PM 21 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:36:05 PM 13 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:36:16 PM 44 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:36:16 PM 8 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:36:19 PM 15 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:39:27 PM 76 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:39:27 PM 73 1363.00 CEUX
GENMAB A/S 27-Mar-25 12:41:48 PM 73 1362.00 XCSE
GENMAB A/S 27-Mar-25 12:41:48 PM 43 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:41:48 PM 77 1362.00 CEUX
GENMAB A/S 27-Mar-25 12:41:48 PM 40 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:41:48 PM 23 1362.50 TQEX
GENMAB A/S 27-Mar-25 12:41:48 PM 22 1362.50 AQEU
GENMAB A/S 27-Mar-25 12:43:08 PM 28 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:43:08 PM 10 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:43:08 PM 13 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:43:16 PM 10 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:43:16 PM 43 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:43:16 PM 77 1362.00 CEUX
GENMAB A/S 27-Mar-25 12:43:23 PM 72 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:43:35 PM 78 1362.00 XCSE
GENMAB A/S 27-Mar-25 12:44:10 PM 24 1361.50 TQEX
GENMAB A/S 27-Mar-25 12:44:10 PM 22 1361.50 AQEU
GENMAB A/S 27-Mar-25 12:44:53 PM 8 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:44:53 PM 9 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:44:53 PM 20 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:44:53 PM 9 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:44:54 PM 14 1363.00 XCSE
GENMAB A/S 27-Mar-25 12:45:02 PM 24 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:02 PM 8 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:02 PM 43 1365.50 XCSE

91

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:45:02 PM 17 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:02 PM 46 1365.00 CEUX
GENMAB A/S 27-Mar-25 12:45:02 PM 28 1365.00 CEUX
GENMAB A/S 27-Mar-25 12:45:02 PM 26 1365.50 AQEU
GENMAB A/S 27-Mar-25 12:45:03 PM 41 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:15 PM 63 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:15 PM 20 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:15 PM 76 1365.00 XCSE
GENMAB A/S 27-Mar-25 12:45:15 PM 15 1365.50 XCSE
GENMAB A/S 27-Mar-25 12:45:15 PM 68 1365.50 CEUX
GENMAB A/S 27-Mar-25 12:45:15 PM 22 1365.50 TQEX
GENMAB A/S 27-Mar-25 12:45:15 PM 34 1365.50 AQEU
GENMAB A/S 27-Mar-25 12:47:02 PM 22 1364.50 TQEX
GENMAB A/S 27-Mar-25 12:47:06 PM 3 1364.50 XCSE
GENMAB A/S 27-Mar-25 12:48:18 PM 73 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:48:18 PM 76 1366.00 CEUX
GENMAB A/S 27-Mar-25 12:48:18 PM 23 1366.00 AQEU
GENMAB A/S 27-Mar-25 12:48:22 PM 33 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:50:00 PM 1 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:01 PM 21 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:13 PM 2 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:14 PM 2 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:17 PM 2 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:21 PM 9 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:21 PM 9 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:21 PM 4 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:50:27 PM 2 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:53:43 PM 15 1368.50 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 15 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 27 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 77 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 41 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 75 1368.50 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 10 1366.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 73 1367.00 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 98 1368.50 XCSE
GENMAB A/S 27-Mar-25 12:55:17 PM 46 1366.00 CEUX
GENMAB A/S 27-Mar-25 12:55:17 PM 76 1368.00 CEUX
GENMAB A/S 27-Mar-25 12:55:17 PM 78 1367.00 CEUX
GENMAB A/S 27-Mar-25 12:55:17 PM 1 1368.00 CEUX
GENMAB A/S 27-Mar-25 12:55:17 PM 29 1367.50 TQEX
GENMAB A/S 27-Mar-25 12:55:17 PM 22 1366.50 TQEX
GENMAB A/S 27-Mar-25 12:55:17 PM 23 1368.00 AQEU
GENMAB A/S 27-Mar-25 12:55:17 PM 22 1367.00 AQEU
GENMAB A/S 27-Mar-25 12:55:17 PM 23 1366.00 AQEU

92

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 12:55:18 PM 11 1365.50 AQEU
GENMAB A/S 27-Mar-25 12:55:21 PM 28 1365.50 AQEU
GENMAB A/S 27-Mar-25 12:55:33 PM 76 1364.50 XCSE
GENMAB A/S 27-Mar-25 12:55:33 PM 9 1364.50 CEUX
GENMAB A/S 27-Mar-25 12:55:33 PM 67 1364.50 CEUX
GENMAB A/S 27-Mar-25 12:55:43 PM 78 1363.50 CEUX
GENMAB A/S 27-Mar-25 12:55:44 PM 19 1363.50 XCSE
GENMAB A/S 27-Mar-25 12:55:44 PM 55 1363.50 XCSE
GENMAB A/S 27-Mar-25 12:55:44 PM 15 1364.00 AQEU
GENMAB A/S 27-Mar-25 12:55:44 PM 9 1364.00 AQEU
GENMAB A/S 27-Mar-25 12:55:51 PM 45 1362.50 CEUX
GENMAB A/S 27-Mar-25 12:55:53 PM 76 1362.50 XCSE
GENMAB A/S 27-Mar-25 12:57:14 PM 27 1363.00 TQEX
GENMAB A/S 27-Mar-25 12:59:36 PM 48 1363.50 XCSE
GENMAB A/S 27-Mar-25 12:59:36 PM 29 1363.50 XCSE
GENMAB A/S 27-Mar-25 1:00:00 PM 48 1363.50 CEUX
GENMAB A/S 27-Mar-25 1:00:26 PM 48 1364.00 XCSE
GENMAB A/S 27-Mar-25 1:00:26 PM 8 1364.00 XCSE
GENMAB A/S 27-Mar-25 1:00:26 PM 13 1364.00 XCSE
GENMAB A/S 27-Mar-25 1:00:51 PM 39 1363.50 CEUX
GENMAB A/S 27-Mar-25 1:04:20 PM 56 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:20 PM 17 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:20 PM 69 1367.50 CEUX
GENMAB A/S 27-Mar-25 1:04:20 PM 40 1367.50 AQEU
GENMAB A/S 27-Mar-25 1:04:21 PM 9 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:21 PM 12 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:21 PM 8 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:21 PM 24 1367.00 TQEX
GENMAB A/S 27-Mar-25 1:04:24 PM 62 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:24 PM 22 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:04:29 PM 36 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 27 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 5 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 21 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 25 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 8 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:04:56 PM 9 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:06:18 PM 24 1367.00 TQEX
GENMAB A/S 27-Mar-25 1:06:29 PM 34 1367.00 AQEU
GENMAB A/S 27-Mar-25 1:08:07 PM 22 1367.00 TQEX
GENMAB A/S 27-Mar-25 1:08:42 PM 40 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:08:42 PM 18 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:08:42 PM 24 1367.00 AQEU
GENMAB A/S 27-Mar-25 1:08:43 PM 42 1367.00 XCSE
GENMAB A/S 27-Mar-25 1:08:56 PM 26 1367.00 XCSE

93

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 1:09:09 PM 10 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 19 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 7 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 9 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 37 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 8 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:09 PM 8 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:09:17 PM 26 1366.50 XCSE
GENMAB A/S 27-Mar-25 1:09:17 PM 50 1366.50 XCSE
GENMAB A/S 27-Mar-25 1:09:18 PM 58 1366.50 CEUX
GENMAB A/S 27-Mar-25 1:09:43 PM 2 1365.50 XCSE
GENMAB A/S 27-Mar-25 1:09:43 PM 73 1365.50 XCSE
GENMAB A/S 27-Mar-25 1:09:48 PM 36 1365.00 CEUX
GENMAB A/S 27-Mar-25 1:11:31 PM 75 1367.00 CEUX
GENMAB A/S 27-Mar-25 1:12:13 PM 40 1367.50 TQEX
GENMAB A/S 27-Mar-25 1:12:18 PM 17 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:12:18 PM 8 1367.50 XCSE
GENMAB A/S 27-Mar-25 1:12:19 PM 25 1367.00 CEUX
GENMAB A/S 27-Mar-25 1:12:19 PM 3 1367.00 CEUX
GENMAB A/S 27-Mar-25 1:12:25 PM 1 1367.00 AQEU
GENMAB A/S 27-Mar-25 1:13:10 PM 34 1368.00 CEUX
GENMAB A/S 27-Mar-25 1:13:26 PM 16 1368.00 XCSE
GENMAB A/S 27-Mar-25 1:13:29 PM 6 1368.00 XCSE
GENMAB A/S 27-Mar-25 1:13:30 PM 26 1368.00 CEUX
GENMAB A/S 27-Mar-25 1:14:23 PM 27 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:23 PM 2 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:23 PM 35 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:24 PM 8 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:24 PM 8 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:24 PM 11 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:14:25 PM 74 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:15:05 PM 74 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:15:08 PM 74 1372.50 CEUX
GENMAB A/S 27-Mar-25 1:15:32 PM 77 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:15:54 PM 72 1371.00 XCSE
GENMAB A/S 27-Mar-25 1:15:54 PM 56 1371.50 CEUX
GENMAB A/S 27-Mar-25 1:19:02 PM 14 1371.50 CEUX
GENMAB A/S 27-Mar-25 1:19:18 PM 14 1371.50 CEUX
GENMAB A/S 27-Mar-25 1:19:37 PM 6 1371.50 CEUX
GENMAB A/S 27-Mar-25 1:19:39 PM 10 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:19:39 PM 33 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:19:39 PM 10 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:19:39 PM 10 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:20:39 PM 14 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:20:39 PM 11 1371.50 XCSE

94

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 1:20:39 PM 50 1371.50 XCSE
GENMAB A/S 27-Mar-25 1:20:39 PM 23 1371.50 TQEX
GENMAB A/S 27-Mar-25 1:21:15 PM 18 1372.50 CEUX
GENMAB A/S 27-Mar-25 1:21:15 PM 57 1372.50 CEUX
GENMAB A/S 27-Mar-25 1:23:06 PM 19 1373.50 XCSE
GENMAB A/S 27-Mar-25 1:23:06 PM 14 1373.50 XCSE
GENMAB A/S 27-Mar-25 1:23:10 PM 44 1373.50 XCSE
GENMAB A/S 27-Mar-25 1:23:10 PM 20 1373.50 XCSE
GENMAB A/S 27-Mar-25 1:23:10 PM 34 1373.50 XCSE
GENMAB A/S 27-Mar-25 1:23:10 PM 76 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:23:10 PM 64 1373.00 CEUX
GENMAB A/S 27-Mar-25 1:23:10 PM 42 1373.00 TQEX
GENMAB A/S 27-Mar-25 1:24:27 PM 4 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:24:35 PM 4 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:25:35 PM 38 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:25:35 PM 68 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:25:35 PM 60 1372.00 XCSE
GENMAB A/S 27-Mar-25 1:26:00 PM 14 1371.50 CEUX
GENMAB A/S 27-Mar-25 1:26:56 PM 43 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 3 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 15 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 9 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 2 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 2 1372.50 XCSE
GENMAB A/S 27-Mar-25 1:26:56 PM 24 1373.00 XCSE
GENMAB A/S 27-Mar-25 1:28:09 PM 42 1375.50 CEUX
GENMAB A/S 27-Mar-25 1:28:09 PM 34 1375.50 CEUX
GENMAB A/S 27-Mar-25 1:28:09 PM 42 1375.50 TQEX
GENMAB A/S 27-Mar-25 1:29:38 PM 36 1375.00 XCSE
GENMAB A/S 27-Mar-25 1:29:38 PM 30 1375.00 XCSE
GENMAB A/S 27-Mar-25 1:29:38 PM 72 1375.00 XCSE
GENMAB A/S 27-Mar-25 1:29:38 PM 22 1375.00 AQEU
GENMAB A/S 27-Mar-25 1:30:31 PM 19 1375.50 XCSE
GENMAB A/S 27-Mar-25 1:30:31 PM 11 1375.50 XCSE
GENMAB A/S 27-Mar-25 1:30:31 PM 22 1375.50 XCSE
GENMAB A/S 27-Mar-25 1:30:31 PM 46 1375.50 XCSE
GENMAB A/S 27-Mar-25 1:33:07 PM 73 1376.00 XCSE
GENMAB A/S 27-Mar-25 1:33:07 PM 26 1376.00 AQEU
GENMAB A/S 27-Mar-25 1:34:14 PM 47 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:34:14 PM 51 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:34:15 PM 41 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:37:15 PM 35 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:37:15 PM 42 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:37:15 PM 21 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:37:15 PM 72 1376.50 CEUX

95

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 1:37:15 PM 32 1376.00 CEUX
GENMAB A/S 27-Mar-25 1:37:15 PM 31 1376.50 AQEU
GENMAB A/S 27-Mar-25 1:37:17 PM 9 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:37:17 PM 10 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:37:17 PM 8 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:37:17 PM 32 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:37:17 PM 18 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:37:17 PM 17 1377.00 XCSE
GENMAB A/S 27-Mar-25 1:37:37 PM 23 1378.00 CEUX
GENMAB A/S 27-Mar-25 1:41:27 PM 26 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 8 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 10 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 11 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 18 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 14 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:27 PM 7 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:41:32 PM 31 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:41:32 PM 40 1378.00 TQEX
GENMAB A/S 27-Mar-25 1:41:42 PM 15 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 15 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 11 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 8 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 26 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 9 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 46 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 10 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 20 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 74 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:42 PM 4 1378.00 CEUX
GENMAB A/S 27-Mar-25 1:41:42 PM 72 1377.50 CEUX
GENMAB A/S 27-Mar-25 1:41:42 PM 3 1377.50 CEUX
GENMAB A/S 27-Mar-25 1:41:42 PM 23 1377.00 TQEX
GENMAB A/S 27-Mar-25 1:41:42 PM 22 1377.50 AQEU
GENMAB A/S 27-Mar-25 1:41:52 PM 8 1377.50 XCSE
GENMAB A/S 27-Mar-25 1:41:56 PM 5 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:41:57 PM 12 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:42:16 PM 45 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:42:16 PM 17 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:42:19 PM 20 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:42:19 PM 14 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:42:30 PM 3 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:24 PM 10 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:24 PM 8 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:44:24 PM 69 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:44:24 PM 9 1378.50 CEUX

96

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 1:44:24 PM 73 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:44:24 PM 22 1378.50 AQEU
GENMAB A/S 27-Mar-25 1:44:25 PM 29 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:25 PM 21 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:25 PM 9 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:25 PM 30 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:44:25 PM 9 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:45:06 PM 14 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:45:06 PM 43 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:45:06 PM 12 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:45:06 PM 10 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:49:06 PM 26 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:49:07 PM 43 1379.00 CEUX
GENMAB A/S 27-Mar-25 1:50:00 PM 12 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 33 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 9 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 10 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 9 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 9 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 1 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 6 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 8 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:00 PM 9 1379.50 XCSE
GENMAB A/S 27-Mar-25 1:50:02 PM 49 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:50:02 PM 76 1379.00 XCSE
GENMAB A/S 27-Mar-25 1:50:02 PM 1 1379.00 CEUX
GENMAB A/S 27-Mar-25 1:50:02 PM 30 1379.00 CEUX
GENMAB A/S 27-Mar-25 1:50:02 PM 40 1379.00 CEUX
GENMAB A/S 27-Mar-25 1:50:02 PM 34 1379.00 CEUX
GENMAB A/S 27-Mar-25 1:50:44 PM 12 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:50:44 PM 19 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:50:46 PM 18 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:50:46 PM 30 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:50:46 PM 15 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:50:46 PM 23 1378.50 TQEX
GENMAB A/S 27-Mar-25 1:50:46 PM 24 1378.50 AQEU
GENMAB A/S 27-Mar-25 1:50:47 PM 44 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:50:47 PM 8 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:50:49 PM 28 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:50:49 PM 44 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:51:01 PM 78 1379.50 CEUX
GENMAB A/S 27-Mar-25 1:51:01 PM 32 1379.50 TQEX
GENMAB A/S 27-Mar-25 1:51:01 PM 7 1379.50 AQEU
GENMAB A/S 27-Mar-25 1:51:01 PM 15 1379.50 AQEU
GENMAB A/S 27-Mar-25 1:51:34 PM 17 1378.50 XCSE

97

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 1:51:34 PM 44 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:51:34 PM 12 1378.50 XCSE
GENMAB A/S 27-Mar-25 1:51:34 PM 69 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:51:34 PM 8 1378.50 CEUX
GENMAB A/S 27-Mar-25 1:51:34 PM 22 1378.50 AQEU
GENMAB A/S 27-Mar-25 1:52:46 PM 22 1377.50 CEUX
GENMAB A/S 27-Mar-25 1:52:46 PM 54 1377.50 CEUX
GENMAB A/S 27-Mar-25 1:53:16 PM 8 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:53:16 PM 9 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:53:16 PM 14 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:53:16 PM 10 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:53:16 PM 13 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:06 PM 9 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:06 PM 32 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:06 PM 6 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:06 PM 9 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:06 PM 8 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:56 PM 9 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:56 PM 6 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:56 PM 10 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:54:56 PM 10 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:55:59 PM 78 1378.00 XCSE
GENMAB A/S 27-Mar-25 1:55:59 PM 73 1377.50 CEUX
GENMAB A/S 27-Mar-25 1:55:59 PM 25 1378.00 TQEX
GENMAB A/S 27-Mar-25 1:55:59 PM 22 1378.00 AQEU
GENMAB A/S 27-Mar-25 1:56:12 PM 72 1377.00 XCSE
GENMAB A/S 27-Mar-25 1:58:48 PM 43 1377.00 XCSE
GENMAB A/S 27-Mar-25 1:58:48 PM 55 1377.00 XCSE
GENMAB A/S 27-Mar-25 1:58:49 PM 48 1377.00 XCSE
GENMAB A/S 27-Mar-25 1:59:14 PM 28 1376.50 AQEU
GENMAB A/S 27-Mar-25 1:59:26 PM 41 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:59:26 PM 32 1376.50 XCSE
GENMAB A/S 27-Mar-25 1:59:43 PM 72 1376.00 CEUX
GENMAB A/S 27-Mar-25 2:00:31 PM 27 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:00:31 PM 73 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:00:57 PM 74 1376.00 CEUX
GENMAB A/S 27-Mar-25 2:01:28 PM 10 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:01:28 PM 78 1376.50 CEUX
GENMAB A/S 27-Mar-25 2:01:28 PM 9 1376.50 TQEX
GENMAB A/S 27-Mar-25 2:01:28 PM 14 1376.50 TQEX
GENMAB A/S 27-Mar-25 2:01:38 PM 2 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:01:57 PM 39 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:04:58 PM 27 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:04:58 PM 23 1376.00 AQEU
GENMAB A/S 27-Mar-25 2:05:19 PM 39 1375.50 XCSE

98

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:05:19 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:05:19 PM 73 1375.50 CEUX
GENMAB A/S 27-Mar-25 2:05:19 PM 22 1375.50 TQEX
GENMAB A/S 27-Mar-25 2:06:06 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 9 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 9 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 7 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 8 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 20 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 9 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 13 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 11 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 10 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:06 PM 8 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:23 PM 8 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:23 PM 20 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:06:23 PM 3 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 44 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 8 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 11 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 9 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 9 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 30 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:25 PM 17 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:46 PM 7 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:46 PM 10 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:46 PM 10 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:07:46 PM 3 1375.00 XCSE
GENMAB A/S 27-Mar-25 2:08:12 PM 24 1374.50 XCSE
GENMAB A/S 27-Mar-25 2:08:12 PM 51 1374.50 XCSE
GENMAB A/S 27-Mar-25 2:08:12 PM 15 1374.50 AQEU
GENMAB A/S 27-Mar-25 2:09:39 PM 30 1374.50 XCSE
GENMAB A/S 27-Mar-25 2:09:39 PM 9 1374.50 XCSE
GENMAB A/S 27-Mar-25 2:09:39 PM 17 1374.50 XCSE
GENMAB A/S 27-Mar-25 2:09:39 PM 58 1374.50 CEUX
GENMAB A/S 27-Mar-25 2:09:39 PM 14 1374.50 CEUX
GENMAB A/S 27-Mar-25 2:09:39 PM 8 1374.50 AQEU
GENMAB A/S 27-Mar-25 2:09:41 PM 23 1374.00 TQEX
GENMAB A/S 27-Mar-25 2:11:06 PM 12 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:11:15 PM 61 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:11:38 PM 30 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:11:38 PM 43 1374.00 XCSE

99

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:11:38 PM 8 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:11:38 PM 17 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:11:38 PM 44 1374.00 CEUX
GENMAB A/S 27-Mar-25 2:11:38 PM 34 1374.00 CEUX
GENMAB A/S 27-Mar-25 2:11:38 PM 30 1373.50 TQEX
GENMAB A/S 27-Mar-25 2:11:38 PM 24 1373.50 AQEU
GENMAB A/S 27-Mar-25 2:12:16 PM 9 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:16 PM 12 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:16 PM 9 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:16 PM 10 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:16 PM 13 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:16 PM 10 1374.00 XCSE
GENMAB A/S 27-Mar-25 2:12:46 PM 24 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:13:18 PM 49 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:14:25 PM 41 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:14:25 PM 10 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:14:25 PM 8 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:14:25 PM 10 1373.00 XCSE
GENMAB A/S 27-Mar-25 2:14:25 PM 49 1373.00 CEUX
GENMAB A/S 27-Mar-25 2:14:25 PM 32 1373.50 CEUX
GENMAB A/S 27-Mar-25 2:14:36 PM 7 1372.50 XCSE
GENMAB A/S 27-Mar-25 2:14:36 PM 7 1372.50 XCSE
GENMAB A/S 27-Mar-25 2:14:36 PM 12 1372.50 XCSE
GENMAB A/S 27-Mar-25 2:14:36 PM 4 1372.50 XCSE
GENMAB A/S 27-Mar-25 2:14:36 PM 10 1372.50 XCSE
GENMAB A/S 27-Mar-25 2:14:41 PM 19 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:14:41 PM 54 1375.50 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 13 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 3 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 43 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 7 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 9 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 15 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 2 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 8 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 12 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 6 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 4 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:10 PM 9 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:16 PM 13 1376.00 XCSE
GENMAB A/S 27-Mar-25 2:17:25 PM 22 1377.00 CEUX
GENMAB A/S 27-Mar-25 2:17:30 PM 12 1377.00 XCSE
GENMAB A/S 27-Mar-25 2:17:31 PM 73 1377.50 XCSE
GENMAB A/S 27-Mar-25 2:17:31 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:18:09 PM 73 1377.00 CEUX

100

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:18:09 PM 22 1377.00 TQEX
GENMAB A/S 27-Mar-25 2:21:23 PM 72 1376.50 XCSE
GENMAB A/S 27-Mar-25 2:21:24 PM 5 1376.50 CEUX
GENMAB A/S 27-Mar-25 2:21:24 PM 36 1376.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 30 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 9 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 1 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:31 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:32 PM 12 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:46 PM 62 1377.50 XCSE
GENMAB A/S 27-Mar-25 2:22:46 PM 31 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:49 PM 62 1377.50 XCSE
GENMAB A/S 27-Mar-25 2:22:49 PM 31 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:22:51 PM 15 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:23:12 PM 5 1377.00 CEUX
GENMAB A/S 27-Mar-25 2:23:29 PM 98 1377.00 XCSE
GENMAB A/S 27-Mar-25 2:23:29 PM 69 1377.00 CEUX
GENMAB A/S 27-Mar-25 2:23:29 PM 42 1377.00 TQEX
GENMAB A/S 27-Mar-25 2:23:29 PM 10 1376.50 AQEU
GENMAB A/S 27-Mar-25 2:23:30 PM 98 1377.00 XCSE
GENMAB A/S 27-Mar-25 2:24:48 PM 4 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:24:49 PM 73 1377.00 CEUX
GENMAB A/S 27-Mar-25 2:24:49 PM 25 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:24:49 PM 4 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:24:49 PM 5 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:24:49 PM 4 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:25:20 PM 10 1378.00 CEUX
GENMAB A/S 27-Mar-25 2:25:41 PM 10 1378.50 XCSE
GENMAB A/S 27-Mar-25 2:25:41 PM 8 1378.50 XCSE
GENMAB A/S 27-Mar-25 2:25:41 PM 7 1378.50 XCSE
GENMAB A/S 27-Mar-25 2:25:41 PM 12 1378.50 XCSE
GENMAB A/S 27-Mar-25 2:26:19 PM 23 1380.50 XCSE
GENMAB A/S 27-Mar-25 2:26:19 PM 62 1380.50 XCSE
GENMAB A/S 27-Mar-25 2:26:19 PM 32 1380.50 CEUX
GENMAB A/S 27-Mar-25 2:26:20 PM 44 1380.50 XCSE
GENMAB A/S 27-Mar-25 2:26:41 PM 12 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:26:41 PM 7 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:26:59 PM 15 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:27:14 PM 10 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:27:23 PM 30 1380.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 17 1381.50 XCSE

101

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:27:26 PM 17 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 1 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 9 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 42 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 7 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 4 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:26 PM 12 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:36 PM 17 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:36 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:36 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:36 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:36 PM 7 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:37 PM 2 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:37 PM 12 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:27:42 PM 4 1381.50 CEUX
GENMAB A/S 27-Mar-25 2:27:50 PM 73 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:28:20 PM 30 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:21 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:21 PM 12 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:21 PM 9 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:21 PM 8 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:30 PM 8 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:28:30 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:29:02 PM 98 1381.00 XCSE
GENMAB A/S 27-Mar-25 2:29:02 PM 74 1379.50 XCSE
GENMAB A/S 27-Mar-25 2:29:02 PM 76 1378.50 XCSE
GENMAB A/S 27-Mar-25 2:29:02 PM 76 1380.50 XCSE
GENMAB A/S 27-Mar-25 2:29:02 PM 77 1381.00 CEUX
GENMAB A/S 27-Mar-25 2:29:02 PM 34 1379.00 CEUX
GENMAB A/S 27-Mar-25 2:29:02 PM 41 1379.00 CEUX
GENMAB A/S 27-Mar-25 2:29:02 PM 72 1380.00 CEUX
GENMAB A/S 27-Mar-25 2:29:02 PM 29 1379.50 TQEX
GENMAB A/S 27-Mar-25 2:29:02 PM 38 1380.50 TQEX
GENMAB A/S 27-Mar-25 2:29:02 PM 32 1378.50 TQEX
GENMAB A/S 27-Mar-25 2:29:02 PM 23 1378.50 AQEU
GENMAB A/S 27-Mar-25 2:29:03 PM 22 1377.50 XCSE
GENMAB A/S 27-Mar-25 2:29:03 PM 50 1377.50 XCSE
GENMAB A/S 27-Mar-25 2:29:03 PM 71 1377.50 CEUX
GENMAB A/S 27-Mar-25 2:29:36 PM 10 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:36 PM 12 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:36 PM 12 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:46 PM 8 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:46 PM 37 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:46 PM 15 1379.00 XCSE

102

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:29:46 PM 11 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:46 PM 8 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:46 PM 8 1379.00 XCSE
GENMAB A/S 27-Mar-25 2:29:48 PM 5 1378.50 CEUX
GENMAB A/S 27-Mar-25 2:30:05 PM 28 1379.50 CEUX
GENMAB A/S 27-Mar-25 2:31:09 PM 1 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:31:09 PM 19 1382.50 CEUX
GENMAB A/S 27-Mar-25 2:31:09 PM 57 1382.50 CEUX
GENMAB A/S 27-Mar-25 2:31:09 PM 26 1382.50 TQEX
GENMAB A/S 27-Mar-25 2:31:15 PM 13 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:31:15 PM 10 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:31:15 PM 22 1381.50 TQEX
GENMAB A/S 27-Mar-25 2:31:21 PM 29 1381.50 XCSE
GENMAB A/S 27-Mar-25 2:31:35 PM 15 1382.50 XCSE
GENMAB A/S 27-Mar-25 2:31:35 PM 1 1382.50 XCSE
GENMAB A/S 27-Mar-25 2:31:35 PM 38 1382.50 XCSE
GENMAB A/S 27-Mar-25 2:31:35 PM 20 1382.50 XCSE
GENMAB A/S 27-Mar-25 2:31:45 PM 30 1382.50 CEUX
GENMAB A/S 27-Mar-25 2:31:48 PM 8 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:31:48 PM 12 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:31:48 PM 9 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:31:50 PM 10 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:31:51 PM 7 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:31:54 PM 13 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:32:01 PM 14 1383.00 XCSE
GENMAB A/S 27-Mar-25 2:32:52 PM 56 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:32:52 PM 29 1385.00 TQEX
GENMAB A/S 27-Mar-25 2:32:53 PM 34 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:33:26 PM 73 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:33:26 PM 24 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:34:21 PM 49 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 2 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 11 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 24 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 4 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 10 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:34:21 PM 74 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:34:21 PM 23 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:34:28 PM 12 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:34:28 PM 33 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:34:29 PM 42 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:34:44 PM 33 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:35:24 PM 31 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:35:24 PM 8 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:35:25 PM 8 1386.00 CEUX

103

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:35:27 PM 10 1385.00 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 5 1385.00 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 67 1385.00 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 14 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 39 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 4 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 31 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:35:27 PM 4 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:35:27 PM 8 1385.00 TQEX
GENMAB A/S 27-Mar-25 2:35:27 PM 11 1385.00 TQEX
GENMAB A/S 27-Mar-25 2:35:27 PM 3 1385.00 TQEX
GENMAB A/S 27-Mar-25 2:35:27 PM 14 1385.50 AQEU
GENMAB A/S 27-Mar-25 2:35:27 PM 26 1385.50 AQEU
GENMAB A/S 27-Mar-25 2:35:57 PM 19 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:35:57 PM 36 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:36:05 PM 42 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:36:05 PM 56 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:36:07 PM 21 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:36:38 PM 19 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:36:39 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:39 PM 17 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:39 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:39 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:52 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:52 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:52 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:52 PM 36 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:36:52 PM 5 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:36:52 PM 5 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:36:52 PM 56 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:36:55 PM 20 1386.50 AQEU
GENMAB A/S 27-Mar-25 2:36:55 PM 2 1386.50 AQEU
GENMAB A/S 27-Mar-25 2:37:01 PM 74 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:37:01 PM 85 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:37:01 PM 24 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:37:01 PM 5 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:01 PM 73 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:37:01 PM 12 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:01 PM 9 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:01 PM 25 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:01 PM 33 1385.50 TQEX
GENMAB A/S 27-Mar-25 2:37:30 PM 8 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:33 PM 28 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:33 PM 25 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:37:33 PM 40 1386.00 CEUX

104

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:38:01 PM 32 1385.50 TQEX
GENMAB A/S 27-Mar-25 2:38:12 PM 14 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:39:14 PM 14 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 55 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 55 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 36 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 7 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 40 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 55 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 3 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:14 PM 29 1388.00 XCSE
GENMAB A/S 27-Mar-25 2:39:20 PM 59 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:39:21 PM 44 1387.50 XCSE
GENMAB A/S 27-Mar-25 2:39:49 PM 23 1387.00 TQEX
GENMAB A/S 27-Mar-25 2:39:49 PM 32 1387.00 AQEU
GENMAB A/S 27-Mar-25 2:40:01 PM 73 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:40:01 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:01 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:01 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:01 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:01 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 30 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 20 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 26 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:02 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 20 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 13 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:03 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:04 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:04 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:04 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:05 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:05 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:05 PM 10 1387.00 XCSE

105

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:40:05 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:05 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:06 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:06 PM 22 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:06 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:06 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:07 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 49 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 17 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:08 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:10 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:10 PM 7 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:10 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:12 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 6 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 30 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 43 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 1 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 10 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:40:13 PM 16 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:40:13 PM 74 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:40:13 PM 15 1387.00 CEUX
GENMAB A/S 27-Mar-25 2:40:13 PM 31 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:40:14 PM 25 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:40:14 PM 40 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:41:05 PM 73 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:41:12 PM 15 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:41:12 PM 13 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:41:12 PM 19 1386.00 XCSE

106

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:41:12 PM 24 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:41:25 PM 28 1385.50 AQEU
GENMAB A/S 27-Mar-25 2:42:15 PM 19 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:42:15 PM 23 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:42:15 PM 13 1386.00 AQEU
GENMAB A/S 27-Mar-25 2:42:16 PM 9 1386.00 AQEU
GENMAB A/S 27-Mar-25 2:42:30 PM 68 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:42:30 PM 10 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:42:30 PM 72 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:42:30 PM 36 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:35 PM 4 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:35 PM 11 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:35 PM 5 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:40 PM 8 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:43 PM 4 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:43 PM 22 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:43 PM 18 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:43 PM 5 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:43 PM 25 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:45 PM 10 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 19 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 22 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 10 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 11 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 9 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 15 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:42:52 PM 41 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:42:59 PM 77 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:42:59 PM 41 1386.00 AQEU
GENMAB A/S 27-Mar-25 2:43:00 PM 13 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:43:00 PM 11 1385.00 XCSE
GENMAB A/S 27-Mar-25 2:43:00 PM 32 1385.00 XCSE
GENMAB A/S 27-Mar-25 2:43:00 PM 24 1385.00 CEUX
GENMAB A/S 27-Mar-25 2:43:05 PM 1 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:43:05 PM 23 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:43:05 PM 42 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:43:11 PM 10 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:43:12 PM 29 1384.50 XCSE
GENMAB A/S 27-Mar-25 2:43:12 PM 30 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:43:27 PM 1 1384.50 CEUX
GENMAB A/S 27-Mar-25 2:44:21 PM 10 1384.00 XCSE
GENMAB A/S 27-Mar-25 2:44:21 PM 30 1384.00 XCSE
GENMAB A/S 27-Mar-25 2:44:21 PM 15 1384.00 CEUX
GENMAB A/S 27-Mar-25 2:44:21 PM 22 1384.00 AQEU
GENMAB A/S 27-Mar-25 2:44:22 PM 20 1384.00 CEUX

107

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:44:22 PM 2 1384.00 CEUX
GENMAB A/S 27-Mar-25 2:44:26 PM 9 1383.50 XCSE
GENMAB A/S 27-Mar-25 2:44:26 PM 9 1383.50 XCSE
GENMAB A/S 27-Mar-25 2:44:26 PM 10 1383.50 XCSE
GENMAB A/S 27-Mar-25 2:44:26 PM 10 1383.50 XCSE
GENMAB A/S 27-Mar-25 2:45:11 PM 74 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:45:11 PM 15 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:45:11 PM 22 1386.00 TQEX
GENMAB A/S 27-Mar-25 2:45:11 PM 24 1386.00 AQEU
GENMAB A/S 27-Mar-25 2:45:20 PM 10 1385.50 XCSE
GENMAB A/S 27-Mar-25 2:45:21 PM 3 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:45:23 PM 4 1385.50 CEUX
GENMAB A/S 27-Mar-25 2:45:33 PM 78 1386.00 CEUX
GENMAB A/S 27-Mar-25 2:45:43 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 13 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 20 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:43 PM 19 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:45:43 PM 58 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:45:45 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 20 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:45 PM 20 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:46 PM 2 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:45:46 PM 1 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:45:47 PM 11 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:47 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:48 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:48 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:48 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:48 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:48 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:51 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:51 PM 19 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:51 PM 1 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:45:52 PM 14 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 10 1387.00 XCSE

108

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:45:52 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 10 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:52 PM 9 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:53 PM 8 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:45:56 PM 7 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:46:01 PM 13 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:46:07 PM 75 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:46:07 PM 22 1387.00 TQEX
GENMAB A/S 27-Mar-25 2:46:07 PM 25 1387.00 AQEU
GENMAB A/S 27-Mar-25 2:46:15 PM 21 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:15 PM 20 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:15 PM 8 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:19 PM 14 1387.00 AQEU
GENMAB A/S 27-Mar-25 2:46:20 PM 74 1387.00 XCSE
GENMAB A/S 27-Mar-25 2:46:26 PM 20 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:46:26 PM 30 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:46:26 PM 10 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:26 PM 1 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:26 PM 14 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:26 PM 10 1387.00 AQEU
GENMAB A/S 27-Mar-25 2:46:30 PM 24 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:46:41 PM 4 1386.00 XCSE
GENMAB A/S 27-Mar-25 2:46:52 PM 74 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:46:52 PM 74 1386.50 CEUX
GENMAB A/S 27-Mar-25 2:46:52 PM 28 1386.00 AQEU
GENMAB A/S 27-Mar-25 2:47:43 PM 74 1386.50 XCSE
GENMAB A/S 27-Mar-25 2:47:59 PM 19 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:03 PM 17 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:06 PM 12 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:09 PM 2 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:11 PM 1 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:11 PM 1 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:11 PM 1 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:11 PM 1 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:15 PM 22 1388.00 CEUX
GENMAB A/S 27-Mar-25 2:48:21 PM 15 1388.00 TQEX
GENMAB A/S 27-Mar-25 2:48:54 PM 72 1389.00 XCSE
GENMAB A/S 27-Mar-25 2:48:54 PM 9 1389.00 XCSE
GENMAB A/S 27-Mar-25 2:48:54 PM 14 1389.00 XCSE
GENMAB A/S 27-Mar-25 2:48:54 PM 3 1389.00 XCSE
GENMAB A/S 27-Mar-25 2:49:24 PM 9 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:49:24 PM 20 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:49:24 PM 10 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:49:24 PM 8 1390.00 XCSE

109

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:49:25 PM 42 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:49:41 PM 20 1389.50 XCSE
GENMAB A/S 27-Mar-25 2:49:41 PM 18 1389.50 CEUX
GENMAB A/S 27-Mar-25 2:49:41 PM 5 1389.50 CEUX
GENMAB A/S 27-Mar-25 2:49:41 PM 45 1389.50 CEUX
GENMAB A/S 27-Mar-25 2:49:41 PM 5 1389.50 CEUX
GENMAB A/S 27-Mar-25 2:49:41 PM 22 1389.50 TQEX
GENMAB A/S 27-Mar-25 2:49:41 PM 22 1389.50 AQEU
GENMAB A/S 27-Mar-25 2:50:27 PM 56 1390.50 XCSE
GENMAB A/S 27-Mar-25 2:50:27 PM 3 1390.50 XCSE
GENMAB A/S 27-Mar-25 2:50:30 PM 68 1391.00 XCSE
GENMAB A/S 27-Mar-25 2:50:32 PM 7 1391.00 XCSE
GENMAB A/S 27-Mar-25 2:50:32 PM 4 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:50:32 PM 1 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:50:32 PM 1 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:50:32 PM 12 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:50:32 PM 25 1391.00 TQEX
GENMAB A/S 27-Mar-25 2:50:46 PM 56 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:50:46 PM 19 1390.50 AQEU
GENMAB A/S 27-Mar-25 2:50:48 PM 60 1390.50 XCSE
GENMAB A/S 27-Mar-25 2:50:48 PM 3 1390.50 AQEU
GENMAB A/S 27-Mar-25 2:51:23 PM 31 1392.00 XCSE
GENMAB A/S 27-Mar-25 2:51:23 PM 46 1392.00 XCSE
GENMAB A/S 27-Mar-25 2:51:23 PM 10 1391.50 CEUX
GENMAB A/S 27-Mar-25 2:51:23 PM 10 1391.50 CEUX
GENMAB A/S 27-Mar-25 2:51:23 PM 2 1391.50 CEUX
GENMAB A/S 27-Mar-25 2:51:23 PM 8 1391.50 CEUX
GENMAB A/S 27-Mar-25 2:51:24 PM 53 1392.00 XCSE
GENMAB A/S 27-Mar-25 2:51:24 PM 27 1392.00 XCSE
GENMAB A/S 27-Mar-25 2:51:31 PM 6 1391.00 XCSE
GENMAB A/S 27-Mar-25 2:51:31 PM 44 1391.50 CEUX
GENMAB A/S 27-Mar-25 2:51:31 PM 26 1391.50 AQEU
GENMAB A/S 27-Mar-25 2:51:34 PM 2 1391.50 AQEU
GENMAB A/S 27-Mar-25 2:51:35 PM 52 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:51:35 PM 21 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:51:35 PM 71 1391.00 XCSE
GENMAB A/S 27-Mar-25 2:51:35 PM 41 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:51:35 PM 31 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:51:35 PM 4 1390.50 AQEU
GENMAB A/S 27-Mar-25 2:51:35 PM 18 1390.50 AQEU
GENMAB A/S 27-Mar-25 2:51:46 PM 10 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:51:59 PM 77 1390.00 XCSE
GENMAB A/S 27-Mar-25 2:51:59 PM 59 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:51:59 PM 6 1390.50 CEUX
GENMAB A/S 27-Mar-25 2:51:59 PM 6 1390.50 TQEX

110

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:51:59 PM 17 1390.50 TQEX
GENMAB A/S 27-Mar-25 2:51:59 PM 2 1390.00 AQEU
GENMAB A/S 27-Mar-25 2:51:59 PM 2 1390.00 AQEU
GENMAB A/S 27-Mar-25 2:52:29 PM 24 1390.00 AQEU
GENMAB A/S 27-Mar-25 2:52:54 PM 2 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:52:54 PM 8 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:53:26 PM 8 1394.00 XCSE
GENMAB A/S 27-Mar-25 2:53:31 PM 74 1393.50 XCSE
GENMAB A/S 27-Mar-25 2:53:50 PM 73 1392.50 XCSE
GENMAB A/S 27-Mar-25 2:53:50 PM 73 1393.00 CEUX
GENMAB A/S 27-Mar-25 2:53:50 PM 10 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:53:50 PM 41 1393.00 TQEX
GENMAB A/S 27-Mar-25 2:54:16 PM 69 1393.00 XCSE
GENMAB A/S 27-Mar-25 2:54:16 PM 9 1393.00 XCSE
GENMAB A/S 27-Mar-25 2:54:16 PM 4 1393.00 CEUX
GENMAB A/S 27-Mar-25 2:54:16 PM 72 1393.00 CEUX
GENMAB A/S 27-Mar-25 2:54:16 PM 28 1393.00 AQEU
GENMAB A/S 27-Mar-25 2:54:20 PM 76 1393.00 XCSE
GENMAB A/S 27-Mar-25 2:54:27 PM 5 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:54:31 PM 5 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:54:31 PM 15 1392.00 CEUX
GENMAB A/S 27-Mar-25 2:55:28 PM 2 1392.50 XCSE
GENMAB A/S 27-Mar-25 2:55:28 PM 28 1392.50 XCSE
GENMAB A/S 27-Mar-25 2:55:30 PM 48 1392.50 XCSE
GENMAB A/S 27-Mar-25 2:56:07 PM 72 1392.50 XCSE
GENMAB A/S 27-Mar-25 2:56:38 PM 10 1394.00 CEUX
GENMAB A/S 27-Mar-25 2:56:38 PM 21 1394.00 CEUX
GENMAB A/S 27-Mar-25 2:56:51 PM 30 1394.00 XCSE
GENMAB A/S 27-Mar-25 2:56:51 PM 47 1394.00 XCSE
GENMAB A/S 27-Mar-25 2:56:51 PM 46 1394.00 CEUX
GENMAB A/S 27-Mar-25 2:57:09 PM 15 1394.00 XCSE
GENMAB A/S 27-Mar-25 2:57:09 PM 9 1394.00 XCSE
GENMAB A/S 27-Mar-25 2:57:24 PM 22 1393.50 TQEX
GENMAB A/S 27-Mar-25 2:57:29 PM 8 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:57:29 PM 32 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:57:29 PM 31 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:57:29 PM 1 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:57:29 PM 16 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:57:29 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 2:58:45 PM 3 1396.00 CEUX
GENMAB A/S 27-Mar-25 2:58:55 PM 29 1397.00 XCSE
GENMAB A/S 27-Mar-25 2:58:55 PM 4 1397.00 XCSE
GENMAB A/S 27-Mar-25 2:58:55 PM 65 1397.00 XCSE
GENMAB A/S 27-Mar-25 2:58:55 PM 95 1397.00 XCSE
GENMAB A/S 27-Mar-25 2:59:28 PM 1 1396.00 CEUX

111

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 2:59:54 PM 12 1398.00 XCSE
GENMAB A/S 27-Mar-25 2:59:54 PM 49 1398.00 XCSE
GENMAB A/S 27-Mar-25 2:59:54 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 2:59:54 PM 27 1398.00 XCSE
GENMAB A/S 27-Mar-25 2:59:56 PM 52 1398.00 XCSE
GENMAB A/S 27-Mar-25 2:59:56 PM 8 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:00:01 PM 9 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:00:09 PM 13 1399.00 CEUX
GENMAB A/S 27-Mar-25 3:00:10 PM 78 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:00:10 PM 45 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:00:10 PM 29 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:00:10 PM 1 1399.00 CEUX
GENMAB A/S 27-Mar-25 3:00:10 PM 22 1398.50 TQEX
GENMAB A/S 27-Mar-25 3:01:01 PM 2 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:01 PM 21 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:01 PM 9 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:01 PM 10 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:01 PM 10 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:01 PM 5 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:01:01 PM 4 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:01:01 PM 2 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:01:01 PM 5 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:01:01 PM 23 1401.50 TQEX
GENMAB A/S 27-Mar-25 3:01:22 PM 76 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:01:22 PM 76 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:01:22 PM 19 1402.50 AQEU
GENMAB A/S 27-Mar-25 3:01:22 PM 3 1402.50 AQEU
GENMAB A/S 27-Mar-25 3:01:23 PM 28 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:01:23 PM 77 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:01:23 PM 48 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:01:23 PM 47 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:01:23 PM 28 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:01:23 PM 76 1400.00 CEUX
GENMAB A/S 27-Mar-25 3:01:23 PM 31 1401.50 AQEU
GENMAB A/S 27-Mar-25 3:01:23 PM 22 1400.00 AQEU
GENMAB A/S 27-Mar-25 3:02:03 PM 72 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:02:03 PM 22 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:02:03 PM 26 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:02:13 PM 75 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:02:13 PM 42 1402.50 TQEX
GENMAB A/S 27-Mar-25 3:02:35 PM 30 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:02:35 PM 22 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:03:07 PM 4 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:03:07 PM 9 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:03:15 PM 25 1402.50 XCSE

112

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:03:34 PM 34 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:03:34 PM 77 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:03:34 PM 23 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:03:43 PM 17 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:03:43 PM 40 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:04:28 PM 29 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:04:51 PM 45 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:04:51 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:04:51 PM 10 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:04:52 PM 12 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:05:27 PM 54 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:05:27 PM 3 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:05:31 PM 63 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:06:45 PM 32 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:07:07 PM 19 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:07:07 PM 17 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:07:13 PM 50 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:07:15 PM 30 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 25 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 13 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 26 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 43 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 16 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 73 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:07:15 PM 76 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:07:15 PM 73 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:07:15 PM 9 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:07:15 PM 22 1403.00 TQEX
GENMAB A/S 27-Mar-25 3:07:15 PM 22 1402.00 TQEX
GENMAB A/S 27-Mar-25 3:07:15 PM 22 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:07:15 PM 29 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:07:17 PM 40 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:07:18 PM 10 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:07:18 PM 14 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:07:21 PM 33 1401.00 AQEU
GENMAB A/S 27-Mar-25 3:07:27 PM 78 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:07:27 PM 34 1400.50 CEUX
GENMAB A/S 27-Mar-25 3:09:00 PM 40 1402.00 TQEX
GENMAB A/S 27-Mar-25 3:09:35 PM 4 1406.00 XCSE
GENMAB A/S 27-Mar-25 3:09:41 PM 55 1406.50 CEUX
GENMAB A/S 27-Mar-25 3:09:41 PM 17 1406.50 CEUX
GENMAB A/S 27-Mar-25 3:09:42 PM 9 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:09:49 PM 73 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:10:03 PM 11 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 73 1408.50 XCSE

113

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:10:04 PM 30 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 9 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 12 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 43 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 4 1409.00 XCSE
GENMAB A/S 27-Mar-25 3:10:04 PM 72 1408.50 CEUX
GENMAB A/S 27-Mar-25 3:10:04 PM 33 1409.00 AQEU
GENMAB A/S 27-Mar-25 3:10:06 PM 72 1408.00 XCSE
GENMAB A/S 27-Mar-25 3:10:06 PM 52 1408.50 CEUX
GENMAB A/S 27-Mar-25 3:10:06 PM 22 1408.50 AQEU
GENMAB A/S 27-Mar-25 3:10:35 PM 9 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 73 1408.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 15 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 15 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 10 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 5 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 15 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 5 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:10:35 PM 48 1407.00 CEUX
GENMAB A/S 27-Mar-25 3:10:35 PM 14 1408.00 CEUX
GENMAB A/S 27-Mar-25 3:10:35 PM 42 1409.00 CEUX
GENMAB A/S 27-Mar-25 3:10:35 PM 13 1408.00 CEUX
GENMAB A/S 27-Mar-25 3:10:35 PM 24 1407.50 AQEU
GENMAB A/S 27-Mar-25 3:10:35 PM 30 1408.50 AQEU
GENMAB A/S 27-Mar-25 3:11:10 PM 22 1408.50 CEUX
GENMAB A/S 27-Mar-25 3:11:22 PM 35 1407.50 XCSE
GENMAB A/S 27-Mar-25 3:11:22 PM 41 1407.50 XCSE
GENMAB A/S 27-Mar-25 3:11:22 PM 27 1407.50 CEUX
GENMAB A/S 27-Mar-25 3:11:22 PM 23 1407.50 AQEU
GENMAB A/S 27-Mar-25 3:12:00 PM 72 1407.00 XCSE
GENMAB A/S 27-Mar-25 3:12:00 PM 22 1407.00 CEUX
GENMAB A/S 27-Mar-25 3:12:00 PM 22 1407.00 TQEX
GENMAB A/S 27-Mar-25 3:12:00 PM 19 1407.00 AQEU
GENMAB A/S 27-Mar-25 3:12:03 PM 5 1407.00 AQEU
GENMAB A/S 27-Mar-25 3:12:06 PM 26 1406.00 XCSE
GENMAB A/S 27-Mar-25 3:12:06 PM 10 1406.00 XCSE
GENMAB A/S 27-Mar-25 3:12:06 PM 40 1406.00 XCSE
GENMAB A/S 27-Mar-25 3:12:11 PM 8 1406.00 AQEU
GENMAB A/S 27-Mar-25 3:12:13 PM 41 1405.50 CEUX
GENMAB A/S 27-Mar-25 3:12:13 PM 24 1406.00 AQEU
GENMAB A/S 27-Mar-25 3:12:43 PM 78 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:12:43 PM 22 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:12:43 PM 24 1405.00 AQEU
GENMAB A/S 27-Mar-25 3:12:43 PM 24 1403.50 AQEU
GENMAB A/S 27-Mar-25 3:12:44 PM 24 1403.00 XCSE

114

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:12:44 PM 50 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:12:59 PM 53 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:12:59 PM 35 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:12:59 PM 17 1402.50 AQEU
GENMAB A/S 27-Mar-25 3:13:19 PM 43 1404.00 XCSE
GENMAB A/S 27-Mar-25 3:13:19 PM 22 1403.50 AQEU
GENMAB A/S 27-Mar-25 3:14:07 PM 18 1404.00 TQEX
GENMAB A/S 27-Mar-25 3:14:10 PM 62 1404.00 XCSE
GENMAB A/S 27-Mar-25 3:14:10 PM 24 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:14:10 PM 16 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:14:10 PM 3 1404.00 AQEU
GENMAB A/S 27-Mar-25 3:14:36 PM 10 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:14:36 PM 4 1404.00 AQEU
GENMAB A/S 27-Mar-25 3:14:36 PM 16 1404.00 AQEU
GENMAB A/S 27-Mar-25 3:14:40 PM 22 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:14:40 PM 30 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:14:48 PM 7 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:14:48 PM 24 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:15:03 PM 43 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:15:03 PM 22 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:15:32 PM 47 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:15:32 PM 21 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:32 PM 36 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:32 PM 5 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:32 PM 20 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:15:32 PM 26 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:15:32 PM 6 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:15:32 PM 2 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:15:32 PM 23 1401.00 TQEX
GENMAB A/S 27-Mar-25 3:15:33 PM 36 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:33 PM 7 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:33 PM 19 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:15:48 PM 60 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:15:51 PM 16 1399.00 CEUX
GENMAB A/S 27-Mar-25 3:15:51 PM 7 1399.00 CEUX
GENMAB A/S 27-Mar-25 3:15:55 PM 3 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:55 PM 21 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:15:55 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:16:14 PM 29 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:16:14 PM 29 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:17:09 PM 19 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:17:13 PM 25 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:17:13 PM 7 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:17:13 PM 29 1396.50 CEUX
GENMAB A/S 27-Mar-25 3:17:13 PM 3 1398.00 CEUX

115

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:17:13 PM 25 1396.50 TQEX
GENMAB A/S 27-Mar-25 3:17:13 PM 23 1398.00 AQEU
GENMAB A/S 27-Mar-25 3:17:13 PM 22 1397.00 AQEU
GENMAB A/S 27-Mar-25 3:17:16 PM 60 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:18:13 PM 15 1397.50 CEUX
GENMAB A/S 27-Mar-25 3:18:34 PM 17 1397.50 CEUX
GENMAB A/S 27-Mar-25 3:19:56 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:19:56 PM 13 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:19:56 PM 41 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:20:34 PM 17 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:20:34 PM 30 1396.50 CEUX
GENMAB A/S 27-Mar-25 3:20:34 PM 22 1396.50 TQEX
GENMAB A/S 27-Mar-25 3:21:09 PM 76 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:21:09 PM 39 1397.00 CEUX
GENMAB A/S 27-Mar-25 3:21:09 PM 22 1397.00 CEUX
GENMAB A/S 27-Mar-25 3:21:17 PM 16 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:21:17 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:21:17 PM 42 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:21:17 PM 42 1397.00 TQEX
GENMAB A/S 27-Mar-25 3:21:17 PM 22 1397.00 AQEU
GENMAB A/S 27-Mar-25 3:21:24 PM 10 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:21:32 PM 10 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:21:32 PM 10 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:21:38 PM 4 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:21:50 PM 39 1396.00 XCSE
GENMAB A/S 27-Mar-25 3:22:05 PM 55 1396.50 CEUX
GENMAB A/S 27-Mar-25 3:22:08 PM 29 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:22:19 PM 11 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:19 PM 11 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:20 PM 47 1397.00 CEUX
GENMAB A/S 27-Mar-25 3:22:28 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:36 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:37 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:37 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:46 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:52 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:22:58 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:23:09 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:24:34 PM 41 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:24:34 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:24:34 PM 24 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:24:34 PM 73 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:25:24 PM 1 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:25:24 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:25:24 PM 2 1399.00 XCSE

116

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:25:24 PM 7 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:25:24 PM 14 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:25:58 PM 7 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:25:58 PM 31 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:25:58 PM 42 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:25:58 PM 18 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:01 PM 42 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:01 PM 12 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:01 PM 10 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:01 PM 8 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:01 PM 10 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:07 PM 11 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:26:07 PM 31 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:26:07 PM 18 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:26:07 PM 42 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:26:07 PM 76 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:26:07 PM 22 1403.00 TQEX
GENMAB A/S 27-Mar-25 3:26:07 PM 11 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:26:07 PM 4 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:26:07 PM 11 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:26:20 PM 10 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:26:20 PM 30 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:26:20 PM 10 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:26:20 PM 1 1403.50 CEUX
GENMAB A/S 27-Mar-25 3:26:20 PM 44 1403.50 CEUX
GENMAB A/S 27-Mar-25 3:26:20 PM 4 1403.50 CEUX
GENMAB A/S 27-Mar-25 3:26:20 PM 2 1403.50 CEUX
GENMAB A/S 27-Mar-25 3:26:20 PM 22 1403.50 TQEX
GENMAB A/S 27-Mar-25 3:26:32 PM 76 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:26:32 PM 67 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:26:32 PM 78 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:26:32 PM 32 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:26:32 PM 28 1403.00 AQEU
GENMAB A/S 27-Mar-25 3:27:09 PM 74 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:27:09 PM 23 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:27:09 PM 3 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:27:09 PM 21 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:27:55 PM 77 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:27:55 PM 28 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:27:55 PM 23 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:27:55 PM 2 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:27:58 PM 77 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:28:19 PM 7 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:28:19 PM 69 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:28:56 PM 5 1402.00 CEUX

117

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:29:11 PM 9 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:29:11 PM 18 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:29:11 PM 5 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:29:11 PM 22 1402.00 TQEX
GENMAB A/S 27-Mar-25 3:29:11 PM 42 1402.00 AQEU
GENMAB A/S 27-Mar-25 3:29:15 PM 12 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:29:16 PM 20 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:29:16 PM 34 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:30:15 PM 73 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:30:15 PM 41 1402.00 TQEX
GENMAB A/S 27-Mar-25 3:31:07 PM 72 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:31:07 PM 60 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:31:10 PM 77 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:31:10 PM 5 1401.50 CEUX
GENMAB A/S 27-Mar-25 3:31:10 PM 18 1401.50 CEUX
GENMAB A/S 27-Mar-25 3:31:50 PM 16 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:32:46 PM 4 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:33:01 PM 10 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:33:01 PM 4 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:33:01 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 8 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 24 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 30 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 77 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 26 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 74 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 10 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:07 PM 48 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:33:07 PM 22 1401.00 AQEU
GENMAB A/S 27-Mar-25 3:33:07 PM 22 1402.50 AQEU
GENMAB A/S 27-Mar-25 3:33:30 PM 73 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:33:30 PM 10 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:30 PM 64 1402.00 XCSE
GENMAB A/S 27-Mar-25 3:33:30 PM 40 1402.50 CEUX
GENMAB A/S 27-Mar-25 3:34:17 PM 72 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:34:17 PM 48 1405.00 CEUX
GENMAB A/S 27-Mar-25 3:34:17 PM 22 1405.00 TQEX
GENMAB A/S 27-Mar-25 3:34:17 PM 22 1405.00 AQEU
GENMAB A/S 27-Mar-25 3:34:28 PM 45 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:35:06 PM 17 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:35:06 PM 13 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:35:06 PM 5 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:35:06 PM 14 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:35:17 PM 77 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:35:38 PM 19 1404.50 CEUX

118

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:35:38 PM 34 1404.50 CEUX
GENMAB A/S 27-Mar-25 3:36:01 PM 10 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:01 PM 10 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:01 PM 9 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:01 PM 8 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:40 PM 38 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:40 PM 60 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:45 PM 5 1404.00 AQEU
GENMAB A/S 27-Mar-25 3:36:56 PM 6 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:36:56 PM 32 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:37:16 PM 47 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:37:36 PM 41 1404.00 XCSE
GENMAB A/S 27-Mar-25 3:37:36 PM 11 1404.00 XCSE
GENMAB A/S 27-Mar-25 3:37:36 PM 43 1404.00 XCSE
GENMAB A/S 27-Mar-25 3:37:42 PM 50 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:37:42 PM 74 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:37:42 PM 30 1404.00 AQEU
GENMAB A/S 27-Mar-25 3:39:58 PM 42 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:39:58 PM 23 1403.50 XCSE
GENMAB A/S 27-Mar-25 3:39:58 PM 22 1403.50 TQEX
GENMAB A/S 27-Mar-25 3:40:04 PM 46 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:40:07 PM 33 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:40:08 PM 42 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:40:08 PM 44 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:40:08 PM 12 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:40:12 PM 13 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:40:12 PM 11 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:40:13 PM 30 1402.50 AQEU
GENMAB A/S 27-Mar-25 3:40:19 PM 53 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:41:10 PM 38 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:41:10 PM 60 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:41:10 PM 29 1404.50 TQEX
GENMAB A/S 27-Mar-25 3:41:10 PM 8 1404.50 AQEU
GENMAB A/S 27-Mar-25 3:41:24 PM 73 1405.00 CEUX
GENMAB A/S 27-Mar-25 3:41:24 PM 24 1405.00 TQEX
GENMAB A/S 27-Mar-25 3:41:44 PM 30 1405.50 XCSE
GENMAB A/S 27-Mar-25 3:41:44 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 3:41:44 PM 22 1405.50 XCSE
GENMAB A/S 27-Mar-25 3:41:44 PM 37 1405.50 XCSE
GENMAB A/S 27-Mar-25 3:41:53 PM 14 1406.00 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 40 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 4 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 40 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 19 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 33 1406.50 XCSE

119

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:42:12 PM 10 1406.50 XCSE
GENMAB A/S 27-Mar-25 3:42:12 PM 30 1406.50 CEUX
GENMAB A/S 27-Mar-25 3:42:12 PM 47 1406.50 CEUX
GENMAB A/S 27-Mar-25 3:42:12 PM 12 1406.50 TQEX
GENMAB A/S 27-Mar-25 3:42:12 PM 22 1406.50 TQEX
GENMAB A/S 27-Mar-25 3:42:28 PM 77 1405.50 XCSE
GENMAB A/S 27-Mar-25 3:42:28 PM 73 1404.50 XCSE
GENMAB A/S 27-Mar-25 3:42:28 PM 77 1405.50 CEUX
GENMAB A/S 27-Mar-25 3:42:28 PM 37 1405.00 AQEU
GENMAB A/S 27-Mar-25 3:42:40 PM 72 1404.00 CEUX
GENMAB A/S 27-Mar-25 3:42:41 PM 78 1403.00 XCSE
GENMAB A/S 27-Mar-25 3:42:41 PM 73 1403.00 CEUX
GENMAB A/S 27-Mar-25 3:42:42 PM 11 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:42:42 PM 12 1402.50 XCSE
GENMAB A/S 27-Mar-25 3:42:46 PM 49 1402.00 CEUX
GENMAB A/S 27-Mar-25 3:42:56 PM 72 1401.50 XCSE
GENMAB A/S 27-Mar-25 3:43:26 PM 62 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:43:26 PM 22 1400.50 CEUX
GENMAB A/S 27-Mar-25 3:44:03 PM 22 1399.00 CEUX
GENMAB A/S 27-Mar-25 3:44:53 PM 4 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:46:20 PM 13 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:46:20 PM 25 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:46:20 PM 1 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:46:20 PM 10 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:46:20 PM 9 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:46:46 PM 72 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:02 PM 11 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:02 PM 1 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:02 PM 7 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:48:02 PM 30 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:02 PM 27 1400.00 TQEX
GENMAB A/S 27-Mar-25 3:48:02 PM 3 1400.00 AQEU
GENMAB A/S 27-Mar-25 3:48:02 PM 21 1400.00 AQEU
GENMAB A/S 27-Mar-25 3:48:03 PM 13 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:48:21 PM 2 1400.50 AQEU
GENMAB A/S 27-Mar-25 3:48:21 PM 2 1400.50 AQEU
GENMAB A/S 27-Mar-25 3:48:21 PM 20 1400.50 AQEU
GENMAB A/S 27-Mar-25 3:48:21 PM 3 1400.50 AQEU
GENMAB A/S 27-Mar-25 3:48:48 PM 42 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:48:48 PM 77 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:48 PM 9 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:48:48 PM 20 1400.50 XCSE
GENMAB A/S 27-Mar-25 3:48:50 PM 1 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:50 PM 12 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:50 PM 9 1400.00 XCSE

120

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:48:50 PM 14 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:48:57 PM 9 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:49:06 PM 14 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:49:06 PM 61 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:49:06 PM 1 1401.00 CEUX
GENMAB A/S 27-Mar-25 3:49:07 PM 9 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:07 PM 21 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:09 PM 20 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:09 PM 26 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:09 PM 42 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:09 PM 10 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:10 PM 37 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:10 PM 10 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:10 PM 8 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:10 PM 42 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:10 PM 8 1401.00 XCSE
GENMAB A/S 27-Mar-25 3:49:17 PM 76 1400.50 CEUX
GENMAB A/S 27-Mar-25 3:49:21 PM 27 1400.00 TQEX
GENMAB A/S 27-Mar-25 3:49:22 PM 14 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:49:22 PM 4 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:49:44 PM 22 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:44 PM 22 1399.00 TQEX
GENMAB A/S 27-Mar-25 3:49:45 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:45 PM 6 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:45 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:45 PM 30 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:45 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:49:45 PM 18 1399.00 AQEU
GENMAB A/S 27-Mar-25 3:49:46 PM 22 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:51:53 PM 42 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:51:53 PM 37 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:51:53 PM 42 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:51:53 PM 37 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:51:53 PM 14 1400.00 XCSE
GENMAB A/S 27-Mar-25 3:51:53 PM 36 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:51:53 PM 2 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:51:53 PM 15 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:51:53 PM 71 1399.50 CEUX
GENMAB A/S 27-Mar-25 3:51:53 PM 7 1399.50 TQEX
GENMAB A/S 27-Mar-25 3:51:53 PM 15 1399.50 TQEX
GENMAB A/S 27-Mar-25 3:51:56 PM 17 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:51:56 PM 11 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 9 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 9 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 42 1398.50 XCSE

121

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:52:46 PM 25 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 25 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:52:46 PM 75 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:52:46 PM 22 1398.50 TQEX
GENMAB A/S 27-Mar-25 3:53:35 PM 9 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:53:35 PM 25 1398.50 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 2 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 14 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 42 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 25 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:58 PM 36 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:54:58 PM 24 1398.00 AQEU
GENMAB A/S 27-Mar-25 3:54:59 PM 18 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:59 PM 39 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:59 PM 29 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:59 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:59 PM 42 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:54:59 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:56:09 PM 74 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:56:09 PM 37 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:56:09 PM 77 1397.00 CEUX
GENMAB A/S 27-Mar-25 3:56:09 PM 40 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:56:09 PM 27 1397.00 TQEX
GENMAB A/S 27-Mar-25 3:56:09 PM 23 1398.00 TQEX
GENMAB A/S 27-Mar-25 3:56:09 PM 22 1397.00 AQEU
GENMAB A/S 27-Mar-25 3:56:09 PM 33 1398.00 AQEU
GENMAB A/S 27-Mar-25 3:56:10 PM 32 1397.00 CEUX
GENMAB A/S 27-Mar-25 3:56:16 PM 1 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:56:16 PM 44 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:56:16 PM 12 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:56:17 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:56:17 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 3:56:56 PM 34 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:56:56 PM 41 1398.50 CEUX
GENMAB A/S 27-Mar-25 3:57:07 PM 29 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:07 PM 18 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:07 PM 30 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:07 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:07 PM 2 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:07 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:08 PM 98 1399.00 XCSE
GENMAB A/S 27-Mar-25 3:57:08 PM 98 1399.00 XCSE

122

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 3:57:21 PM 29 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:57:21 PM 46 1397.50 XCSE
GENMAB A/S 27-Mar-25 3:57:21 PM 32 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:57:21 PM 40 1398.00 AQEU
GENMAB A/S 27-Mar-25 3:57:39 PM 9 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:59:49 PM 76 1398.00 XCSE
GENMAB A/S 27-Mar-25 3:59:49 PM 32 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:59:49 PM 24 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:59:49 PM 25 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:59:52 PM 28 1398.00 CEUX
GENMAB A/S 27-Mar-25 3:59:52 PM 25 1398.00 AQEU
GENMAB A/S 27-Mar-25 4:00:03 PM 26 1398.50 TQEX
GENMAB A/S 27-Mar-25 4:00:05 PM 26 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:05 PM 8 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:05 PM 1 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:05 PM 10 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:05 PM 8 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:05 PM 36 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:05 PM 4 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:05 PM 5 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:05 PM 5 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:11 PM 15 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:11 PM 1 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:00:11 PM 4 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:11 PM 5 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:11 PM 5 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:11 PM 5 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:12 PM 15 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:00:45 PM 74 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:01:06 PM 41 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:06 PM 12 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:06 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:06 PM 77 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:01:06 PM 36 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:01:06 PM 22 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:01:07 PM 12 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 78 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:07 PM 32 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:01:21 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 32 1398.00 XCSE

123

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:01:21 PM 78 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 77 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 2 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:01:21 PM 72 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:01:21 PM 5 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:01:21 PM 33 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:01:22 PM 11 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:01:22 PM 9 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:01:22 PM 16 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 20 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 7 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:01:34 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 73 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 45 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 2 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 14 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 10 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 41 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:05:02 PM 75 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:05:02 PM 75 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:05:02 PM 25 1396.50 TQEX
GENMAB A/S 27-Mar-25 4:05:02 PM 11 1396.50 AQEU
GENMAB A/S 27-Mar-25 4:05:02 PM 11 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:05:02 PM 19 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:05:02 PM 15 1396.50 AQEU
GENMAB A/S 27-Mar-25 4:05:12 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 24 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:12 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:05:17 PM 10 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:05:17 PM 6 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:05:17 PM 5 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:05:17 PM 5 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:05:47 PM 73 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:05:47 PM 36 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:05:47 PM 4 1398.50 CEUX

124

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:05:47 PM 3 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:05:47 PM 34 1398.50 AQEU
GENMAB A/S 27-Mar-25 4:06:21 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:06:21 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:06:21 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:06:21 PM 6 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:06:21 PM 24 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:07:20 PM 36 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:07:20 PM 33 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:07:48 PM 8 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:07:48 PM 36 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:07:48 PM 21 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:07:48 PM 14 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:07:48 PM 29 1400.00 TQEX
GENMAB A/S 27-Mar-25 4:07:55 PM 1 1400.00 AQEU
GENMAB A/S 27-Mar-25 4:08:07 PM 44 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:07 PM 75 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:07 PM 15 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:08:07 PM 24 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:08:07 PM 34 1400.00 AQEU
GENMAB A/S 27-Mar-25 4:08:11 PM 30 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:08:11 PM 36 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:08:11 PM 72 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:08:21 PM 19 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:21 PM 41 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:21 PM 3 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:22 PM 10 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:40 PM 26 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:40 PM 30 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:08:40 PM 36 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:08:59 PM 74 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:09:02 PM 12 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:09:36 PM 19 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:36 PM 30 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:40 PM 10 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:10:42 PM 28 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 48 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 45 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 11 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 30 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 25 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 1 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:42 PM 6 1399.50 XCSE

125

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:10:42 PM 30 1399.00 TQEX
GENMAB A/S 27-Mar-25 4:10:42 PM 29 1399.00 AQEU
GENMAB A/S 27-Mar-25 4:10:43 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:43 PM 30 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:43 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:43 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 77 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 12 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:10:48 PM 4 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:10:48 PM 5 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:10:48 PM 4 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:10:48 PM 25 1399.00 TQEX
GENMAB A/S 27-Mar-25 4:11:09 PM 73 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:11:10 PM 3 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:11:12 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 15 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 38 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 44 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 37 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 6 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 11 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:12 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 16 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 45 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 39 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 3 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:13 PM 38 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 14 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 25 1399.00 XCSE

126

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:11:14 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 14 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 45 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 38 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:14 PM 13 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:15 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:15 PM 9 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:15 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:16 PM 8 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:23 PM 13 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 38 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 8 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 17 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:41 PM 8 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:11:48 PM 36 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:48 PM 10 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:11:55 PM 13 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:12:37 PM 10 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 8 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 17 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 45 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 3 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 8 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 32 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 10 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 10 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:37 PM 8 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:46 PM 9 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:50 PM 14 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:12:53 PM 36 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:12:56 PM 7 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:12:57 PM 8 1400.00 XCSE
GENMAB A/S 27-Mar-25 4:13:05 PM 36 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:06 PM 41 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:06 PM 20 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:28 PM 47 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:29 PM 5 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:29 PM 4 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:29 PM 36 1400.00 CEUX

127

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:13:29 PM 5 1400.00 CEUX
GENMAB A/S 27-Mar-25 4:13:44 PM 12 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:44 PM 39 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:44 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:44 PM 4 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:13:44 PM 36 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:13:44 PM 4 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:13:44 PM 5 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:13:45 PM 44 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 17 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 7 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 18 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 9 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 7 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:54 PM 22 1399.50 CEUX
GENMAB A/S 27-Mar-25 4:13:55 PM 2 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:55 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:55 PM 10 1399.50 XCSE
GENMAB A/S 27-Mar-25 4:13:58 PM 74 1399.00 XCSE
GENMAB A/S 27-Mar-25 4:13:58 PM 75 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:13:58 PM 22 1399.00 TQEX
GENMAB A/S 27-Mar-25 4:13:58 PM 23 1399.00 AQEU
GENMAB A/S 27-Mar-25 4:14:18 PM 78 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:14:18 PM 23 1398.00 TQEX
GENMAB A/S 27-Mar-25 4:14:18 PM 10 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:14:26 PM 72 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:14:26 PM 16 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:14:27 PM 25 1397.00 TQEX
GENMAB A/S 27-Mar-25 4:15:02 PM 27 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:15:02 PM 19 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:15:02 PM 16 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:15:04 PM 5 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:15:18 PM 53 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:15:59 PM 10 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:16:08 PM 5 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:16:29 PM 10 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:16:29 PM 12 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:16:29 PM 11 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:16:59 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:16:59 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:16:59 PM 1 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:16:59 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:16:59 PM 9 1397.00 XCSE

128

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:16:59 PM 8 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:16:59 PM 32 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:17:14 PM 30 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:17:14 PM 20 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:17:14 PM 15 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:17:23 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:23 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:23 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:23 PM 26 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:23 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 8 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 9 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 1 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 10 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 11 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 44 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 29 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 12 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 11 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:17:53 PM 22 1396.50 TQEX
GENMAB A/S 27-Mar-25 4:17:54 PM 17 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:54 PM 2 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:55 PM 13 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:55 PM 3 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:55 PM 25 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:55 PM 13 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:56 PM 18 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:56 PM 8 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:56 PM 9 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:56 PM 1 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:58 PM 9 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:17:58 PM 10 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:09 PM 28 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:18:09 PM 17 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:18:39 PM 26 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:39 PM 7 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:39 PM 8 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:39 PM 17 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:39 PM 8 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:18:39 PM 8 1396.50 XCSE

129

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:18:39 PM 78 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:18:39 PM 10 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:18:39 PM 28 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:18:39 PM 21 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:18:40 PM 11 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:19:08 PM 72 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:20:49 PM 76 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:20:50 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:20:51 PM 2 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:20:51 PM 6 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:21:11 PM 75 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:21:11 PM 32 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:21:29 PM 19 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:21:31 PM 7 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:22:08 PM 15 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:08 PM 45 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:08 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:08 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:08 PM 1 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:08 PM 1 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:22:08 PM 69 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:22:08 PM 31 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:22:08 PM 37 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:22:28 PM 65 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:22:34 PM 19 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:22:45 PM 32 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:22:52 PM 21 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:22:55 PM 49 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:23:03 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:23:03 PM 30 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:23:03 PM 34 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:23:08 PM 44 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:23:08 PM 4 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:23:59 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:23:59 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:23:59 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:24:01 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:24:13 PM 12 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:13 PM 19 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:24:13 PM 36 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:24:17 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:17 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:17 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:17 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:17 PM 8 1397.00 XCSE

130

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:24:17 PM 16 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 43 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 41 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 11 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 18 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:18 PM 28 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:19 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:24:44 PM 1 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:24:44 PM 30 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:24:44 PM 1 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:24:44 PM 16 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:24:44 PM 7 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:25:29 PM 17 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:25:29 PM 9 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:25:29 PM 21 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:25:29 PM 12 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:26:08 PM 3 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 46 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 42 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 30 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 14 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 11 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 12 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 13 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 28 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:08 PM 26 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:26:08 PM 24 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:26:08 PM 29 1396.50 TQEX
GENMAB A/S 27-Mar-25 4:26:08 PM 25 1396.50 AQEU
GENMAB A/S 27-Mar-25 4:26:09 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 28 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 9 1397.00 XCSE

131

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:26:09 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 25 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 1 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 45 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:09 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 2 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:10 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:11 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:13 PM 14 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:15 PM 29 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:15 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:16 PM 29 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:16 PM 36 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:26:21 PM 78 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:26:56 PM 12 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:26:56 PM 16 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:27:04 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:27:08 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:08 PM 42 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:08 PM 28 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:08 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:08 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:27 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:27 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:27 PM 23 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:27 PM 5 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:27 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:54 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:54 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:27:54 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:28:11 PM 10 1397.50 XCSE

132

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:28:14 PM 7 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:28:32 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:28:37 PM 10 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:28:37 PM 11 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:29:06 PM 9 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:29:50 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:29:50 PM 5 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:29:54 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:29:54 PM 25 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:29:54 PM 1 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 75 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:03 PM 42 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:03 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 30 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 30 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:03 PM 37 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:30:03 PM 20 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:30:03 PM 27 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:30:05 PM 19 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:05 PM 30 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:05 PM 2 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:05 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:05 PM 35 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:05 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:05 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:25 PM 1 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:34 PM 29 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 24 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 1 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 13 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 2 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 12 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:34 PM 2 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:40 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:40 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:40 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:41 PM 7 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:46 PM 11 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 75 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 9 1398.00 XCSE

133

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:30:50 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:30:50 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:50 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:50 PM 28 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:30:50 PM 19 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:30:50 PM 4 1397.50 AQEU
GENMAB A/S 27-Mar-25 4:30:51 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:51 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:51 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:30:52 PM 12 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:30:52 PM 4 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:30:52 PM 15 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:30:52 PM 19 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:05 PM 13 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:33 PM 19 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:33 PM 24 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:35 PM 22 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:41 PM 10 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:31:52 PM 78 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:31:52 PM 48 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:31:52 PM 75 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:31:52 PM 39 1395.00 CEUX
GENMAB A/S 27-Mar-25 4:31:52 PM 23 1395.50 TQEX
GENMAB A/S 27-Mar-25 4:31:52 PM 28 1396.50 TQEX
GENMAB A/S 27-Mar-25 4:31:52 PM 38 1395.50 AQEU
GENMAB A/S 27-Mar-25 4:31:52 PM 25 1396.50 AQEU
GENMAB A/S 27-Mar-25 4:31:56 PM 14 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:31:56 PM 10 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:31:56 PM 11 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:31:56 PM 13 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:31:56 PM 1 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:31:56 PM 41 1395.00 XCSE
GENMAB A/S 27-Mar-25 4:32:15 PM 24 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:32:15 PM 31 1394.50 TQEX
GENMAB A/S 27-Mar-25 4:32:15 PM 24 1394.00 AQEU
GENMAB A/S 27-Mar-25 4:32:19 PM 54 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:32:26 PM 43 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:32:26 PM 8 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:32:58 PM 2 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:32:58 PM 43 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:00 PM 32 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:33:14 PM 45 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:14 PM 10 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:14 PM 8 1393.50 XCSE

134

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:33:14 PM 22 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:14 PM 10 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:14 PM 76 1393.50 CEUX
GENMAB A/S 27-Mar-25 4:33:26 PM 7 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:26 PM 16 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:26 PM 17 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:38 PM 38 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:39 PM 31 1393.50 XCSE
GENMAB A/S 27-Mar-25 4:33:49 PM 34 1393.50 TQEX
GENMAB A/S 27-Mar-25 4:33:49 PM 17 1393.50 AQEU
GENMAB A/S 27-Mar-25 4:33:57 PM 9 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:33:57 PM 5 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:33:57 PM 27 1394.00 XCSE
GENMAB A/S 27-Mar-25 4:34:06 PM 16 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:34:16 PM 19 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:16 PM 9 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:17 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:17 PM 12 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:26 PM 8 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:26 PM 9 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:26 PM 19 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:36 PM 14 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:36 PM 5 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:38 PM 19 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:34:46 PM 8 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:46 PM 8 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:47 PM 15 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:56 PM 7 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:34:56 PM 17 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:35:22 PM 40 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:35:22 PM 34 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:35:22 PM 39 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:35:22 PM 10 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:35:22 PM 23 1394.50 AQEU
GENMAB A/S 27-Mar-25 4:35:30 PM 33 1394.50 AQEU
GENMAB A/S 27-Mar-25 4:36:02 PM 36 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:03 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:03 PM 9 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 9 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 45 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 11 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 24 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:11 PM 9 1394.00 CEUX

135

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:36:11 PM 3 1394.00 CEUX
GENMAB A/S 27-Mar-25 4:36:13 PM 3 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:20 PM 6 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:20 PM 30 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:21 PM 41 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:44 PM 9 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:44 PM 10 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:36:44 PM 36 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:45 PM 28 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:36:59 PM 53 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:37:00 PM 45 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:37:00 PM 18 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:37:00 PM 19 1394.50 XCSE
GENMAB A/S 27-Mar-25 4:37:00 PM 55 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:37:27 PM 77 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:37:27 PM 11 1395.50 CEUX
GENMAB A/S 27-Mar-25 4:37:27 PM 9 1395.50 CEUX
GENMAB A/S 27-Mar-25 4:37:31 PM 65 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:37:31 PM 13 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:37:31 PM 43 1396.50 CEUX
GENMAB A/S 27-Mar-25 4:37:31 PM 16 1395.50 CEUX
GENMAB A/S 27-Mar-25 4:37:31 PM 19 1396.00 TQEX
GENMAB A/S 27-Mar-25 4:37:31 PM 3 1396.00 TQEX
GENMAB A/S 27-Mar-25 4:37:31 PM 35 1396.00 AQEU
GENMAB A/S 27-Mar-25 4:38:04 PM 25 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:38:11 PM 61 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:11 PM 48 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:38:11 PM 17 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:11 PM 72 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:11 PM 36 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:38:11 PM 27 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:38:11 PM 29 1397.00 TQEX
GENMAB A/S 27-Mar-25 4:38:11 PM 23 1398.00 TQEX
GENMAB A/S 27-Mar-25 4:38:26 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:26 PM 22 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:26 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:26 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:26 PM 13 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:26 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 22 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 12 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 8 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:38:46 PM 13 1397.00 XCSE

136

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:38:49 PM 76 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:38:49 PM 4 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:38:49 PM 7 1395.50 CEUX
GENMAB A/S 27-Mar-25 4:38:49 PM 3 1395.50 CEUX
GENMAB A/S 27-Mar-25 4:38:49 PM 3 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:38:50 PM 4 1394.50 CEUX
GENMAB A/S 27-Mar-25 4:39:26 PM 11 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:26 PM 9 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:26 PM 7 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:26 PM 13 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:26 PM 10 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:45 PM 2 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:45 PM 10 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:45 PM 9 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:45 PM 17 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:49 PM 10 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:49 PM 9 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:49 PM 10 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:39:49 PM 22 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:40:18 PM 42 1395.50 XCSE
GENMAB A/S 27-Mar-25 4:40:26 PM 3 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:40:27 PM 1 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:40:27 PM 6 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:16 PM 4 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:41:16 PM 4 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:41:16 PM 36 1396.00 CEUX
GENMAB A/S 27-Mar-25 4:41:22 PM 32 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:22 PM 19 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:22 PM 2 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:22 PM 45 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:26 PM 9 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:26 PM 8 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:38 PM 63 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:55 PM 4 1396.00 XCSE
GENMAB A/S 27-Mar-25 4:41:56 PM 27 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:42:24 PM 44 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:24 PM 54 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:25 PM 12 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:42:27 PM 20 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:42:28 PM 66 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:42:29 PM 78 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:42:29 PM 19 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:42:29 PM 27 1398.00 TQEX
GENMAB A/S 27-Mar-25 4:42:29 PM 23 1398.00 AQEU
GENMAB A/S 27-Mar-25 4:42:50 PM 36 1397.50 CEUX

137

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:42:50 PM 34 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:42:50 PM 21 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:42:50 PM 23 1397.00 TQEX
GENMAB A/S 27-Mar-25 4:42:50 PM 23 1397.00 AQEU
GENMAB A/S 27-Mar-25 4:42:51 PM 50 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 45 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 29 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 10 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 38 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 5 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:51 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 30 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 8 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:42:52 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:43:06 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:43:08 PM 53 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:43:08 PM 9 1398.00 XCSE
GENMAB A/S 27-Mar-25 4:43:24 PM 19 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:43:36 PM 13 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:43:36 PM 27 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:43:36 PM 4 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:43:36 PM 45 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:43:36 PM 9 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:43:40 PM 7 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:43:40 PM 63 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:43:52 PM 25 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:43:52 PM 56 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:43:52 PM 22 1398.00 AQEU
GENMAB A/S 27-Mar-25 4:44:24 PM 8 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:44:24 PM 9 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:44:24 PM 14 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:44:24 PM 41 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:44:31 PM 78 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:44:31 PM 36 1398.00 CEUX
GENMAB A/S 27-Mar-25 4:44:54 PM 22 1398.00 AQEU
GENMAB A/S 27-Mar-25 4:45:12 PM 73 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:45:12 PM 24 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:45:28 PM 42 1397.50 XCSE

138

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:45:40 PM 35 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:45:44 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:45:44 PM 21 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:45:44 PM 9 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:46:02 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:46:02 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:46:02 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:46:02 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:46:03 PM 11 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:03 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:46:07 PM 7 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:07 PM 14 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:08 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:09 PM 12 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:13 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:14 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:18 PM 11 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:18 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:19 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:23 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:23 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:24 PM 13 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:46:29 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:46:29 PM 78 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:46:29 PM 10 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:46:29 PM 5 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:29 PM 45 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:29 PM 4 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:29 PM 65 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:29 PM 4 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:29 PM 27 1397.00 AQEU
GENMAB A/S 27-Mar-25 4:46:30 PM 16 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:46:30 PM 12 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:46:30 PM 15 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:30 PM 37 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:46:41 PM 9 1397.00 XCSE
GENMAB A/S 27-Mar-25 4:47:01 PM 20 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:01 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:01 PM 8 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:01 PM 34 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:01 PM 24 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:02 PM 7 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:09 PM 15 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:19 PM 11 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:47:19 PM 15 1397.50 CEUX

139

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:47:19 PM 17 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:48:21 PM 35 1396.50 XCSE
GENMAB A/S 27-Mar-25 4:48:22 PM 9 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:48:22 PM 63 1397.00 CEUX
GENMAB A/S 27-Mar-25 4:49:47 PM 9 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:47 PM 36 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:54 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:49:54 PM 8 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:49:54 PM 9 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:49:54 PM 10 1397.50 XCSE
GENMAB A/S 27-Mar-25 4:49:54 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:54 PM 5 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:54 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 9 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 23 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:49:55 PM 2 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:49:55 PM 2 1397.50 TQEX
GENMAB A/S 27-Mar-25 4:49:58 PM 8 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:50:16 PM 4 1397.50 CEUX
GENMAB A/S 27-Mar-25 4:50:16 PM 39 1398.00 AQEU
GENMAB A/S 27-Mar-25 4:50:19 PM 98 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:50:19 PM 78 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:50:19 PM 74 1398.50 CEUX
GENMAB A/S 27-Mar-25 4:50:20 PM 13 1398.50 AQEU
GENMAB A/S 27-Mar-25 4:50:31 PM 36 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:50:31 PM 78 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:50:31 PM 24 1399.00 CEUX
GENMAB A/S 27-Mar-25 4:50:31 PM 2 1399.00 TQEX
GENMAB A/S 27-Mar-25 4:50:31 PM 2 1399.00 TQEX
GENMAB A/S 27-Mar-25 4:50:37 PM 32 1398.50 XCSE
GENMAB A/S 27-Mar-25 4:51:00 PM 71 1402.00 CEUX
GENMAB A/S 27-Mar-25 4:51:00 PM 27 1402.00 CEUX
GENMAB A/S 27-Mar-25 4:51:00 PM 24 1402.00 CEUX
GENMAB A/S 27-Mar-25 4:51:00 PM 11 1402.00 TQEX
GENMAB A/S 27-Mar-25 4:51:00 PM 11 1402.00 TQEX
GENMAB A/S 27-Mar-25 4:51:09 PM 74 1401.50 XCSE
GENMAB A/S 27-Mar-25 4:51:09 PM 32 1402.00 CEUX
GENMAB A/S 27-Mar-25 4:51:09 PM 2 1402.00 TQEX
GENMAB A/S 27-Mar-25 4:51:09 PM 11 1402.00 TQEX
GENMAB A/S 27-Mar-25 4:51:09 PM 2 1402.00 TQEX
GENMAB A/S 27-Mar-25 4:51:09 PM 23 1401.50 TQEX
GENMAB A/S 27-Mar-25 4:51:09 PM 29 1401.50 AQEU

140

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:51:16 PM 77 1401.50 XCSE
GENMAB A/S 27-Mar-25 4:51:23 PM 25 1402.00 CEUX
GENMAB A/S 27-Mar-25 4:51:46 PM 3 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:46 PM 11 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:46 PM 22 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:47 PM 36 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:47 PM 25 1403.00 AQEU
GENMAB A/S 27-Mar-25 4:51:51 PM 8 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 73 1402.50 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 10 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 17 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 24 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 28 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 10 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:51 PM 25 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 4 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 5 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 36 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 2 1403.00 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 44 1402.50 CEUX
GENMAB A/S 27-Mar-25 4:51:51 PM 31 1402.50 TQEX
GENMAB A/S 27-Mar-25 4:51:51 PM 10 1402.00 AQEU
GENMAB A/S 27-Mar-25 4:51:52 PM 8 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 13 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 8 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 8 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 9 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 30 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 2 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 6 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 1 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 8 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:51:52 PM 14 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:52:03 PM 10 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:52:03 PM 45 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:52:03 PM 31 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:52:03 PM 9 1403.00 XCSE

141

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:52:03 PM 3 1403.00 XCSE
GENMAB A/S 27-Mar-25 4:52:19 PM 30 1403.50 CEUX
GENMAB A/S 27-Mar-25 4:52:19 PM 3 1403.50 TQEX
GENMAB A/S 27-Mar-25 4:52:19 PM 19 1403.50 TQEX
GENMAB A/S 27-Mar-25 4:52:20 PM 25 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 31 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 64 1403.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 45 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 22 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 2 1403.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 73 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:52:30 PM 17 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:52:30 PM 2 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:52:30 PM 32 1405.00 CEUX
GENMAB A/S 27-Mar-25 4:52:30 PM 22 1405.00 CEUX
GENMAB A/S 27-Mar-25 4:52:30 PM 6 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:52:30 PM 26 1404.50 TQEX
GENMAB A/S 27-Mar-25 4:52:30 PM 11 1403.50 TQEX
GENMAB A/S 27-Mar-25 4:52:30 PM 23 1404.00 AQEU
GENMAB A/S 27-Mar-25 4:52:30 PM 12 1404.50 AQEU
GENMAB A/S 27-Mar-25 4:52:31 PM 22 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:52:31 PM 25 1404.00 AQEU
GENMAB A/S 27-Mar-25 4:52:32 PM 18 1404.00 TQEX
GENMAB A/S 27-Mar-25 4:52:43 PM 51 1404.00 XCSE
GENMAB A/S 27-Mar-25 4:52:50 PM 12 1404.00 TQEX
GENMAB A/S 27-Mar-25 4:53:16 PM 10 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:53:18 PM 17 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 4 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 2 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:35 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:36 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:36 PM 4 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:36 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:38 PM 4 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:38 PM 4 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:38 PM 4 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:38 PM 36 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:39 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:39 PM 5 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:53:39 PM 4 1404.50 CEUX

142

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 27-Mar-25 4:53:49 PM 8 1403.50 XCSE
GENMAB A/S 27-Mar-25 4:53:57 PM 10 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:53:57 PM 10 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:54:03 PM 17 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:54:10 PM 41 1404.00 CEUX
GENMAB A/S 27-Mar-25 4:54:13 PM 19 1404.00 TQEX
GENMAB A/S 27-Mar-25 4:54:13 PM 10 1404.00 TQEX
GENMAB A/S 27-Mar-25 4:54:21 PM 45 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:54:21 PM 8 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:54:21 PM 10 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:54:21 PM 10 1404.50 XCSE
GENMAB A/S 27-Mar-25 4:54:29 PM 78 1404.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 10 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 1 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 9 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 9 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 45 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:37 PM 14 1404.50 CEUX
GENMAB A/S 27-Mar-25 4:54:38 PM 10 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:38 PM 17 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:38 PM 45 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:38 PM 8 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:38 PM 10 1405.00 XCSE
GENMAB A/S 27-Mar-25 4:54:52 PM 28 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 11 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 30 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 10 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 30 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 10 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 8 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 8 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:53 PM 30 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:54 PM 10 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:54 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:54 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:56 PM 30 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:56 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:56 PM 9 1405.50 XCSE
GENMAB A/S 27-Mar-25 4:54:56 PM 10 1405.50 XCSE
GENMAB A/S 28-Mar-25 10:09:21 AM 16 1387.00 TQEX
GENMAB A/S 28-Mar-25 10:10:35 AM 62 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:10:35 AM 64 1387.00 XCSE

143

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 10:10:35 AM 73 1386.00 CEUX
GENMAB A/S 28-Mar-25 10:10:35 AM 50 1387.00 TQEX
GENMAB A/S 28-Mar-25 10:10:35 AM 64 1386.00 TQEX
GENMAB A/S 28-Mar-25 10:10:35 AM 71 1386.50 AQEU
GENMAB A/S 28-Mar-25 10:10:35 AM 49 1385.50 AQEU
GENMAB A/S 28-Mar-25 10:10:35 AM 21 1385.50 AQEU
GENMAB A/S 28-Mar-25 10:12:11 AM 59 1387.50 CEUX
GENMAB A/S 28-Mar-25 10:12:11 AM 8 1387.50 AQEU
GENMAB A/S 28-Mar-25 10:12:11 AM 14 1387.50 AQEU
GENMAB A/S 28-Mar-25 10:21:09 AM 36 1388.50 CEUX
GENMAB A/S 28-Mar-25 10:21:09 AM 25 1388.50 CEUX
GENMAB A/S 28-Mar-25 10:21:09 AM 79 1388.50 CEUX
GENMAB A/S 28-Mar-25 10:21:09 AM 25 1388.50 TQEX
GENMAB A/S 28-Mar-25 10:21:09 AM 22 1388.50 AQEU
GENMAB A/S 28-Mar-25 10:21:10 AM 17 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:21:13 AM 10 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:22:43 AM 55 1389.50 XCSE
GENMAB A/S 28-Mar-25 10:22:43 AM 23 1389.50 XCSE
GENMAB A/S 28-Mar-25 10:22:43 AM 36 1389.50 CEUX
GENMAB A/S 28-Mar-25 10:22:45 AM 34 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:22:45 AM 15 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:22:54 AM 41 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:22:54 AM 11 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:22:54 AM 30 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:24:35 AM 36 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:25:32 AM 1 1389.50 XCSE
GENMAB A/S 28-Mar-25 10:25:32 AM 73 1389.50 XCSE
GENMAB A/S 28-Mar-25 10:25:32 AM 28 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:25:39 AM 20 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 53 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 26 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 12 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 21 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 41 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 28 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 32 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:25:39 AM 15 1389.00 CEUX
GENMAB A/S 28-Mar-25 10:25:40 AM 58 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:12 AM 41 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:12 AM 26 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:12 AM 30 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:12 AM 36 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:26:28 AM 26 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:28 AM 41 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:28 AM 30 1390.00 XCSE

144

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 10:26:28 AM 4 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:26:28 AM 24 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:26:29 AM 79 1389.50 XCSE
GENMAB A/S 28-Mar-25 10:26:29 AM 5 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:26:29 AM 5 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:26:29 AM 17 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:26:29 AM 14 1389.50 TQEX
GENMAB A/S 28-Mar-25 10:26:38 AM 10 1390.50 CEUX
GENMAB A/S 28-Mar-25 10:26:38 AM 13 1390.50 CEUX
GENMAB A/S 28-Mar-25 10:26:38 AM 43 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:26:43 AM 22 1390.50 TQEX
GENMAB A/S 28-Mar-25 10:27:44 AM 54 1391.00 XCSE
GENMAB A/S 28-Mar-25 10:27:44 AM 34 1391.00 XCSE
GENMAB A/S 28-Mar-25 10:27:44 AM 13 1391.00 XCSE
GENMAB A/S 28-Mar-25 10:27:44 AM 33 1391.00 XCSE
GENMAB A/S 28-Mar-25 10:27:45 AM 28 1391.50 TQEX
GENMAB A/S 28-Mar-25 10:28:46 AM 43 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:28:46 AM 41 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:28:46 AM 78 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:28:46 AM 17 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:28:46 AM 80 1392.00 CEUX
GENMAB A/S 28-Mar-25 10:28:46 AM 24 1392.00 AQEU
GENMAB A/S 28-Mar-25 10:29:45 AM 17 1393.00 XCSE
GENMAB A/S 28-Mar-25 10:29:45 AM 41 1393.00 XCSE
GENMAB A/S 28-Mar-25 10:29:45 AM 43 1393.00 XCSE
GENMAB A/S 28-Mar-25 10:29:45 AM 32 1392.50 CEUX
GENMAB A/S 28-Mar-25 10:29:45 AM 26 1392.50 TQEX
GENMAB A/S 28-Mar-25 10:29:49 AM 76 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:29:49 AM 61 1392.50 XCSE
GENMAB A/S 28-Mar-25 10:29:49 AM 14 1392.00 CEUX
GENMAB A/S 28-Mar-25 10:29:49 AM 66 1392.00 CEUX
GENMAB A/S 28-Mar-25 10:29:51 AM 45 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:29:51 AM 14 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:30:05 AM 78 1392.00 XCSE
GENMAB A/S 28-Mar-25 10:30:05 AM 17 1392.00 CEUX
GENMAB A/S 28-Mar-25 10:30:05 AM 62 1392.00 CEUX
GENMAB A/S 28-Mar-25 10:30:19 AM 30 1391.50 XCSE
GENMAB A/S 28-Mar-25 10:30:19 AM 41 1391.50 XCSE
GENMAB A/S 28-Mar-25 10:30:19 AM 16 1391.50 XCSE
GENMAB A/S 28-Mar-25 10:30:20 AM 79 1391.00 XCSE
GENMAB A/S 28-Mar-25 10:30:20 AM 76 1391.00 CEUX
GENMAB A/S 28-Mar-25 10:31:38 AM 79 1390.00 XCSE
GENMAB A/S 28-Mar-25 10:31:38 AM 75 1390.00 CEUX
GENMAB A/S 28-Mar-25 10:32:12 AM 29 1389.00 TQEX
GENMAB A/S 28-Mar-25 10:32:24 AM 76 1388.50 XCSE

145

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 10:32:24 AM 76 1388.50 CEUX
GENMAB A/S 28-Mar-25 10:32:25 AM 2 1387.50 XCSE
GENMAB A/S 28-Mar-25 10:32:25 AM 77 1387.50 XCSE
GENMAB A/S 28-Mar-25 10:32:26 AM 45 1387.00 CEUX
GENMAB A/S 28-Mar-25 10:32:28 AM 11 1387.00 CEUX
GENMAB A/S 28-Mar-25 10:32:30 AM 74 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:32:30 AM 12 1385.50 CEUX
GENMAB A/S 28-Mar-25 10:32:30 AM 35 1385.50 CEUX
GENMAB A/S 28-Mar-25 10:33:05 AM 14 1384.50 CEUX
GENMAB A/S 28-Mar-25 10:33:12 AM 6 1385.00 AQEU
GENMAB A/S 28-Mar-25 10:33:35 AM 77 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:33:35 AM 25 1386.50 CEUX
GENMAB A/S 28-Mar-25 10:33:35 AM 3 1386.50 TQEX
GENMAB A/S 28-Mar-25 10:35:26 AM 74 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:36:00 AM 76 1385.50 XCSE
GENMAB A/S 28-Mar-25 10:36:00 AM 25 1385.50 CEUX
GENMAB A/S 28-Mar-25 10:37:31 AM 33 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:37:31 AM 17 1386.50 CEUX
GENMAB A/S 28-Mar-25 10:38:57 AM 52 1386.50 CEUX
GENMAB A/S 28-Mar-25 10:40:02 AM 30 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:02 AM 80 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:02 AM 41 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:02 AM 12 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:02 AM 73 1386.50 CEUX
GENMAB A/S 28-Mar-25 10:40:02 AM 27 1386.00 TQEX
GENMAB A/S 28-Mar-25 10:40:02 AM 22 1386.50 AQEU
GENMAB A/S 28-Mar-25 10:40:03 AM 18 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:03 AM 43 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:40:37 AM 50 1387.50 CEUX
GENMAB A/S 28-Mar-25 10:44:41 AM 26 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:44:41 AM 55 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:44:41 AM 13 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:44:41 AM 23 1387.00 TQEX
GENMAB A/S 28-Mar-25 10:44:52 AM 13 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:44:52 AM 7 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 12 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 41 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 30 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 53 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 7 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 11 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 18 1387.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 13 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 12 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 30 1386.00 XCSE

146

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 10:45:50 AM 79 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 35 1386.50 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 41 1386.00 XCSE
GENMAB A/S 28-Mar-25 10:45:50 AM 56 1385.50 CEUX
GENMAB A/S 28-Mar-25 10:45:50 AM 58 1386.50 CEUX
GENMAB A/S 28-Mar-25 10:45:50 AM 5 1386.00 TQEX
GENMAB A/S 28-Mar-25 10:45:50 AM 26 1386.50 AQEU
GENMAB A/S 28-Mar-25 10:45:51 AM 23 1385.50 XCSE
GENMAB A/S 28-Mar-25 10:46:02 AM 27 1385.50 XCSE
GENMAB A/S 28-Mar-25 10:46:02 AM 30 1385.50 XCSE
GENMAB A/S 28-Mar-25 10:46:14 AM 15 1385.00 AQEU
GENMAB A/S 28-Mar-25 10:46:44 AM 10 1384.50 XCSE
GENMAB A/S 28-Mar-25 10:46:44 AM 58 1384.50 XCSE
GENMAB A/S 28-Mar-25 10:46:44 AM 29 1385.00 TQEX
GENMAB A/S 28-Mar-25 10:46:44 AM 1 1385.00 AQEU
GENMAB A/S 28-Mar-25 10:47:06 AM 9 1384.50 XCSE
GENMAB A/S 28-Mar-25 10:48:07 AM 24 1384.00 CEUX
GENMAB A/S 28-Mar-25 10:48:10 AM 12 1384.00 XCSE
GENMAB A/S 28-Mar-25 10:48:10 AM 41 1384.00 XCSE
GENMAB A/S 28-Mar-25 10:48:21 AM 41 1384.00 XCSE
GENMAB A/S 28-Mar-25 10:48:21 AM 6 1384.00 XCSE
GENMAB A/S 28-Mar-25 10:48:41 AM 77 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:48:41 AM 64 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:48:41 AM 16 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:48:41 AM 23 1383.50 TQEX
GENMAB A/S 28-Mar-25 10:48:41 AM 38 1383.50 AQEU
GENMAB A/S 28-Mar-25 10:49:21 AM 74 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:49:21 AM 9 1382.00 TQEX
GENMAB A/S 28-Mar-25 10:49:21 AM 20 1382.00 TQEX
GENMAB A/S 28-Mar-25 10:49:26 AM 24 1382.00 AQEU
GENMAB A/S 28-Mar-25 10:51:01 AM 27 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:51:01 AM 19 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:51:01 AM 14 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:51:01 AM 41 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:51:01 AM 4 1382.00 AQEU
GENMAB A/S 28-Mar-25 10:51:24 AM 77 1381.00 XCSE
GENMAB A/S 28-Mar-25 10:51:24 AM 59 1381.00 CEUX
GENMAB A/S 28-Mar-25 10:51:24 AM 15 1381.00 CEUX
GENMAB A/S 28-Mar-25 10:51:24 AM 23 1381.50 TQEX
GENMAB A/S 28-Mar-25 10:51:24 AM 24 1381.00 AQEU
GENMAB A/S 28-Mar-25 10:52:02 AM 76 1380.00 XCSE
GENMAB A/S 28-Mar-25 10:52:02 AM 13 1380.00 CEUX
GENMAB A/S 28-Mar-25 10:52:02 AM 25 1381.50 CEUX
GENMAB A/S 28-Mar-25 10:52:02 AM 66 1380.00 CEUX
GENMAB A/S 28-Mar-25 10:52:02 AM 2 1380.00 AQEU

147

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 10:52:10 AM 51 1381.50 CEUX
GENMAB A/S 28-Mar-25 10:54:31 AM 37 1382.50 XCSE
GENMAB A/S 28-Mar-25 10:54:31 AM 36 1382.50 XCSE
GENMAB A/S 28-Mar-25 10:54:31 AM 15 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:54:31 AM 9 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:54:31 AM 50 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:57:47 AM 13 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:47 AM 41 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:47 AM 41 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:47 AM 11 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:47 AM 11 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:47 AM 12 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:48 AM 11 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:48 AM 12 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:48 AM 41 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 41 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 11 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 41 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 11 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 38 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 30 1383.00 XCSE
GENMAB A/S 28-Mar-25 10:57:50 AM 78 1382.50 CEUX
GENMAB A/S 28-Mar-25 10:57:50 AM 16 1382.00 AQEU
GENMAB A/S 28-Mar-25 10:58:09 AM 78 1382.00 XCSE
GENMAB A/S 28-Mar-25 10:58:09 AM 26 1382.00 TQEX
GENMAB A/S 28-Mar-25 10:58:09 AM 15 1382.00 AQEU
GENMAB A/S 28-Mar-25 10:59:21 AM 77 1381.00 XCSE
GENMAB A/S 28-Mar-25 10:59:21 AM 32 1381.50 CEUX
GENMAB A/S 28-Mar-25 10:59:21 AM 26 1381.50 CEUX
GENMAB A/S 28-Mar-25 10:59:21 AM 14 1381.00 AQEU
GENMAB A/S 28-Mar-25 10:59:21 AM 8 1381.00 AQEU
GENMAB A/S 28-Mar-25 11:00:37 AM 13 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:00:37 AM 18 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:00:37 AM 74 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:00:37 AM 22 1380.50 TQEX
GENMAB A/S 28-Mar-25 11:00:57 AM 2 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:00:57 AM 14 1380.00 AQEU
GENMAB A/S 28-Mar-25 11:03:27 AM 22 1382.00 TQEX
GENMAB A/S 28-Mar-25 11:04:01 AM 40 1381.50 XCSE
GENMAB A/S 28-Mar-25 11:04:01 AM 40 1381.50 XCSE
GENMAB A/S 28-Mar-25 11:04:01 AM 75 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:05:47 AM 4 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:06:28 AM 37 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:06:28 AM 11 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:06:28 AM 10 1381.50 CEUX

148

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:06:51 AM 22 1381.00 TQEX
GENMAB A/S 28-Mar-25 11:06:51 AM 15 1381.00 AQEU
GENMAB A/S 28-Mar-25 11:06:52 AM 72 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:06:52 AM 19 1381.00 AQEU
GENMAB A/S 28-Mar-25 11:07:11 AM 8 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:07:11 AM 3 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:09:59 AM 8 1382.50 CEUX
GENMAB A/S 28-Mar-25 11:10:09 AM 71 1382.50 CEUX
GENMAB A/S 28-Mar-25 11:10:09 AM 15 1382.50 CEUX
GENMAB A/S 28-Mar-25 11:11:49 AM 41 1382.50 XCSE
GENMAB A/S 28-Mar-25 11:11:49 AM 1 1382.50 XCSE
GENMAB A/S 28-Mar-25 11:11:51 AM 20 1382.00 XCSE
GENMAB A/S 28-Mar-25 11:13:00 AM 59 1382.00 XCSE
GENMAB A/S 28-Mar-25 11:13:04 AM 31 1382.00 TQEX
GENMAB A/S 28-Mar-25 11:13:07 AM 23 1382.00 CEUX
GENMAB A/S 28-Mar-25 11:13:07 AM 25 1382.00 AQEU
GENMAB A/S 28-Mar-25 11:13:11 AM 12 1382.00 XCSE
GENMAB A/S 28-Mar-25 11:13:11 AM 32 1382.00 CEUX
GENMAB A/S 28-Mar-25 11:13:11 AM 73 1382.50 CEUX
GENMAB A/S 28-Mar-25 11:13:11 AM 28 1382.50 CEUX
GENMAB A/S 28-Mar-25 11:13:11 AM 1 1382.00 TQEX
GENMAB A/S 28-Mar-25 11:13:11 AM 34 1382.00 TQEX
GENMAB A/S 28-Mar-25 11:13:19 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:19 AM 78 1381.50 XCSE
GENMAB A/S 28-Mar-25 11:13:19 AM 65 1381.50 CEUX
GENMAB A/S 28-Mar-25 11:13:19 AM 23 1381.00 TQEX
GENMAB A/S 28-Mar-25 11:13:19 AM 6 1381.00 AQEU
GENMAB A/S 28-Mar-25 11:13:19 AM 20 1381.00 AQEU
GENMAB A/S 28-Mar-25 11:13:20 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:20 AM 42 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:20 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:20 AM 59 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:20 AM 9 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:13:21 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:21 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:22 AM 9 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:22 AM 92 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:22 AM 101 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:23 AM 3 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:23 AM 62 1381.00 XCSE
GENMAB A/S 28-Mar-25 11:13:32 AM 77 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:13:32 AM 80 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:13:32 AM 34 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:13:32 AM 33 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:13:32 AM 8 1380.00 AQEU

149

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:13:43 AM 74 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:13:43 AM 20 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:13:43 AM 57 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:13:45 AM 22 1378.50 AQEU
GENMAB A/S 28-Mar-25 11:14:23 AM 10 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:14:23 AM 69 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:15:58 AM 20 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:16:00 AM 17 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:16:21 AM 1 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:16:21 AM 13 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:16:38 AM 16 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:16:51 AM 41 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:16:51 AM 11 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:16:51 AM 12 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:17:17 AM 75 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:18:20 AM 17 1377.50 AQEU
GENMAB A/S 28-Mar-25 11:18:26 AM 59 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:18:26 AM 30 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:18:26 AM 5 1377.50 AQEU
GENMAB A/S 28-Mar-25 11:18:45 AM 25 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:18:45 AM 3 1377.50 TQEX
GENMAB A/S 28-Mar-25 11:18:53 AM 53 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:18:53 AM 19 1377.50 TQEX
GENMAB A/S 28-Mar-25 11:19:04 AM 45 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:19:04 AM 15 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:20:00 AM 21 1376.50 TQEX
GENMAB A/S 28-Mar-25 11:20:01 AM 9 1377.00 XCSE
GENMAB A/S 28-Mar-25 11:20:01 AM 61 1377.00 XCSE
GENMAB A/S 28-Mar-25 11:21:14 AM 3 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:21:15 AM 18 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:21:15 AM 41 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:21:15 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:21:39 AM 25 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:21:39 AM 8 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:21:39 AM 38 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:23:33 AM 52 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:33 AM 49 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:33 AM 11 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:23:33 AM 20 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:23:52 AM 41 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:52 AM 13 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:52 AM 13 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:53 AM 11 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:53 AM 33 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:23:53 AM 26 1378.50 XCSE

150

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:24:37 AM 45 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:25:57 AM 35 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:25:57 AM 36 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:25:58 AM 1 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:26:42 AM 41 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:26:42 AM 41 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:26:42 AM 11 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:26:42 AM 31 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:28:06 AM 76 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:28:06 AM 41 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:28:06 AM 14 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:28:06 AM 66 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:28:06 AM 32 1378.50 TQEX
GENMAB A/S 28-Mar-25 11:28:06 AM 39 1378.50 AQEU
GENMAB A/S 28-Mar-25 11:28:47 AM 27 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:29:08 AM 34 1379.50 TQEX
GENMAB A/S 28-Mar-25 11:29:18 AM 36 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:30:28 AM 75 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:30:28 AM 28 1379.00 AQEU
GENMAB A/S 28-Mar-25 11:30:30 AM 41 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:30:30 AM 23 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:30:30 AM 1 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:31:58 AM 10 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:31:58 AM 7 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:31:58 AM 5 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:31:59 AM 1 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:31:59 AM 33 1378.50 TQEX
GENMAB A/S 28-Mar-25 11:32:00 AM 77 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:32:00 AM 5 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:32:00 AM 44 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:32:00 AM 30 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:32:00 AM 22 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:32:58 AM 26 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:32:58 AM 44 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:33:21 AM 14 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:33:22 AM 41 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:33:22 AM 11 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:33:27 AM 26 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:34:17 AM 52 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:34:46 AM 15 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:34:46 AM 25 1379.00 TQEX
GENMAB A/S 28-Mar-25 11:35:08 AM 68 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:35:08 AM 11 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:35:08 AM 32 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:35:10 AM 41 1379.00 XCSE

151

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:35:52 AM 11 1379.00 XCSE
GENMAB A/S 28-Mar-25 11:36:37 AM 24 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:36:37 AM 36 1379.00 CEUX
GENMAB A/S 28-Mar-25 11:36:47 AM 41 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 31 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 13 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 12 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 17 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 12 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:47 AM 41 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 27 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 41 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 30 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 13 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 41 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 19 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:36:48 AM 11 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:37:21 AM 13 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:37:21 AM 37 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:37:55 AM 10 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:37:55 AM 12 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:37:55 AM 13 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:19 AM 9 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:19 AM 13 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:43 AM 12 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:43 AM 41 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:43 AM 31 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:38:50 AM 16 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:38:57 AM 34 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:39:03 AM 32 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:39:16 AM 32 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:40:12 AM 26 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:40:22 AM 44 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:40:22 AM 77 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:40:22 AM 50 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:40:22 AM 10 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:40:22 AM 69 1379.50 CEUX
GENMAB A/S 28-Mar-25 11:40:22 AM 39 1379.50 TQEX
GENMAB A/S 28-Mar-25 11:42:16 AM 5 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:42:16 AM 80 1381.00 CEUX
GENMAB A/S 28-Mar-25 11:44:27 AM 18 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:44:27 AM 73 1380.50 XCSE
GENMAB A/S 28-Mar-25 11:44:27 AM 22 1380.50 TQEX
GENMAB A/S 28-Mar-25 11:44:27 AM 22 1380.50 AQEU
GENMAB A/S 28-Mar-25 11:44:28 AM 43 1380.50 XCSE

152

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:44:38 AM 3 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:44:38 AM 53 1380.50 CEUX
GENMAB A/S 28-Mar-25 11:45:05 AM 59 1380.00 CEUX
GENMAB A/S 28-Mar-25 11:45:05 AM 20 1380.00 CEUX
GENMAB A/S 28-Mar-25 11:45:37 AM 22 1380.00 XCSE
GENMAB A/S 28-Mar-25 11:45:37 AM 1 1380.00 XCSE
GENMAB A/S 28-Mar-25 11:46:46 AM 12 1380.00 AQEU
GENMAB A/S 28-Mar-25 11:47:13 AM 25 1380.00 AQEU
GENMAB A/S 28-Mar-25 11:47:21 AM 79 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:47:34 AM 24 1379.50 TQEX
GENMAB A/S 28-Mar-25 11:47:44 AM 23 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:47:44 AM 11 1379.50 XCSE
GENMAB A/S 28-Mar-25 11:47:55 AM 14 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:48:30 AM 14 1378.50 TQEX
GENMAB A/S 28-Mar-25 11:48:47 AM 58 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:49:57 AM 22 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:52:34 AM 21 1378.50 XCSE
GENMAB A/S 28-Mar-25 11:52:34 AM 28 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:52:35 AM 14 1378.50 CEUX
GENMAB A/S 28-Mar-25 11:52:35 AM 8 1378.50 TQEX
GENMAB A/S 28-Mar-25 11:54:27 AM 74 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:54:27 AM 36 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:54:27 AM 23 1377.50 TQEX
GENMAB A/S 28-Mar-25 11:54:28 AM 8 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:54:28 AM 31 1377.00 XCSE
GENMAB A/S 28-Mar-25 11:54:28 AM 36 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:54:29 AM 26 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:54:29 AM 43 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:54:29 AM 1 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:54:29 AM 53 1377.50 XCSE
GENMAB A/S 28-Mar-25 11:56:17 AM 12 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:56:17 AM 14 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:56:51 AM 16 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:56:51 AM 17 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:56:51 AM 12 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:56:51 AM 30 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:56:52 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:56:52 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:56:53 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:56:57 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:56:59 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:00 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:10 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 13 1378.00 XCSE

153

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 11:57:15 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:15 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:16 AM 14 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:57:17 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:17 AM 30 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:17 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:17 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:17 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:17 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:18 AM 37 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:18 AM 13 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:18 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:18 AM 35 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:57:29 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:29 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:55 AM 31 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:55 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:56 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:56 AM 11 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:56 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:56 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:56 AM 12 1377.50 CEUX
GENMAB A/S 28-Mar-25 11:57:57 AM 12 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:57:59 AM 7 1378.00 XCSE
GENMAB A/S 28-Mar-25 11:59:40 AM 46 1377.00 XCSE
GENMAB A/S 28-Mar-25 11:59:40 AM 79 1378.00 CEUX
GENMAB A/S 28-Mar-25 11:59:46 AM 6 1378.00 CEUX
GENMAB A/S 28-Mar-25 12:02:27 PM 20 1377.50 CEUX
GENMAB A/S 28-Mar-25 12:02:28 PM 44 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:28 PM 1 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 14 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 41 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 10 1376.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 13 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 15 1376.50 XCSE

154

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:02:46 PM 9 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 13 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 12 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 9 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 79 1376.00 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 41 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 4 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 30 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 16 1377.50 XCSE
GENMAB A/S 28-Mar-25 12:02:46 PM 36 1377.50 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 20 1377.00 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 44 1376.50 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 34 1376.50 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 5 1377.00 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 5 1377.00 CEUX
GENMAB A/S 28-Mar-25 12:02:46 PM 11 1376.50 TQEX
GENMAB A/S 28-Mar-25 12:02:46 PM 15 1376.50 TQEX
GENMAB A/S 28-Mar-25 12:02:47 PM 18 1376.00 XCSE
GENMAB A/S 28-Mar-25 12:02:47 PM 19 1375.50 CEUX
GENMAB A/S 28-Mar-25 12:02:55 PM 33 1375.50 CEUX
GENMAB A/S 28-Mar-25 12:02:55 PM 22 1375.50 CEUX
GENMAB A/S 28-Mar-25 12:03:35 PM 41 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:03:35 PM 78 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:03:35 PM 15 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:03:35 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:03:35 PM 28 1375.00 TQEX
GENMAB A/S 28-Mar-25 12:03:37 PM 23 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:03:37 PM 54 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:03:38 PM 35 1374.50 XCSE
GENMAB A/S 28-Mar-25 12:03:38 PM 33 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:03:38 PM 43 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:03:38 PM 44 1374.50 XCSE
GENMAB A/S 28-Mar-25 12:03:38 PM 27 1374.00 TQEX
GENMAB A/S 28-Mar-25 12:06:43 PM 77 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:08:25 PM 23 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:09:07 PM 55 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:09:13 PM 30 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:09:13 PM 29 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:09:37 PM 50 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:10:46 PM 10 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:10:46 PM 20 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:10:46 PM 34 1375.00 CEUX
GENMAB A/S 28-Mar-25 12:11:17 PM 14 1375.00 CEUX
GENMAB A/S 28-Mar-25 12:11:45 PM 29 1375.00 CEUX
GENMAB A/S 28-Mar-25 12:11:58 PM 32 1375.00 TQEX

155

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:12:10 PM 2 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:10 PM 25 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:10 PM 41 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:10 PM 8 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:10 PM 3 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:10 PM 30 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:12 PM 4 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:12 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:47 PM 23 1374.50 AQEU
GENMAB A/S 28-Mar-25 12:12:48 PM 32 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:48 PM 11 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:48 PM 39 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:48 PM 11 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:48 PM 15 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:12:49 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:49 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:49 PM 41 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:49 PM 11 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:49 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:49 PM 32 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:50 PM 11 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:50 PM 10 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:50 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:50 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:50 PM 13 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:51 PM 5 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:51 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:12:51 PM 28 1375.00 XCSE
GENMAB A/S 28-Mar-25 12:13:03 PM 16 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:13:03 PM 58 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:13:03 PM 75 1373.50 XCSE
GENMAB A/S 28-Mar-25 12:13:03 PM 61 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:13:03 PM 10 1372.00 CEUX
GENMAB A/S 28-Mar-25 12:13:03 PM 70 1372.00 CEUX
GENMAB A/S 28-Mar-25 12:13:03 PM 79 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:13:03 PM 27 1372.50 TQEX
GENMAB A/S 28-Mar-25 12:13:03 PM 3 1372.50 TQEX
GENMAB A/S 28-Mar-25 12:13:03 PM 22 1373.50 TQEX
GENMAB A/S 28-Mar-25 12:13:03 PM 23 1373.50 AQEU
GENMAB A/S 28-Mar-25 12:13:03 PM 18 1372.00 AQEU
GENMAB A/S 28-Mar-25 12:13:03 PM 4 1372.00 AQEU
GENMAB A/S 28-Mar-25 12:13:04 PM 15 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:13:04 PM 18 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:13:18 PM 44 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:13:18 PM 24 1371.50 TQEX

156

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:14:23 PM 3 1371.50 TQEX
GENMAB A/S 28-Mar-25 12:18:22 PM 44 1371.50 CEUX
GENMAB A/S 28-Mar-25 12:18:47 PM 5 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 11 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 12 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 30 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 30 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 35 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 12 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 24 1371.50 XCSE
GENMAB A/S 28-Mar-25 12:18:47 PM 43 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:18:48 PM 74 1370.50 XCSE
GENMAB A/S 28-Mar-25 12:18:48 PM 74 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:18:48 PM 6 1369.00 CEUX
GENMAB A/S 28-Mar-25 12:18:48 PM 77 1370.50 CEUX
GENMAB A/S 28-Mar-25 12:18:48 PM 55 1369.00 CEUX
GENMAB A/S 28-Mar-25 12:18:48 PM 31 1370.50 TQEX
GENMAB A/S 28-Mar-25 12:19:10 PM 8 1368.50 XCSE
GENMAB A/S 28-Mar-25 12:19:10 PM 60 1368.50 XCSE
GENMAB A/S 28-Mar-25 12:20:42 PM 75 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:24:21 PM 53 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:24:21 PM 1 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:24:21 PM 6 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:24:21 PM 9 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:25:21 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:25:21 PM 19 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:25:21 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:26:10 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:26:10 PM 22 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:26:57 PM 42 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:32:27 PM 1 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:32:27 PM 53 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:32:27 PM 16 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:32:27 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:32:28 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:32:39 PM 12 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:32:39 PM 48 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:32:39 PM 39 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:32:53 PM 12 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:32:53 PM 46 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:32:53 PM 43 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:34:17 PM 32 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:34:17 PM 77 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:34:17 PM 14 1372.50 TQEX
GENMAB A/S 28-Mar-25 12:34:17 PM 25 1372.50 TQEX

157

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:34:44 PM 15 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:34:44 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 42 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 22 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 30 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 50 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 32 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 30 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 21 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 16 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:35:33 PM 4 1372.00 AQEU
GENMAB A/S 28-Mar-25 12:35:34 PM 2 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:34 PM 8 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:34 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:34 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:34 PM 1 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:35 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:35 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:35 PM 30 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:35 PM 30 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:36 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:36 PM 2 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:35:36 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:36 PM 37 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:35:36 PM 30 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:36:27 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:36:27 PM 42 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:36:27 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:36:27 PM 32 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:37:11 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:37:11 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:37:11 PM 32 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:38:00 PM 2 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:38:24 PM 96 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:38:28 PM 4 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:38:28 PM 59 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:38:32 PM 10 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:39:21 PM 74 1372.50 XCSE
GENMAB A/S 28-Mar-25 12:39:21 PM 1 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:41:44 PM 25 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:41:44 PM 5 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:41:44 PM 70 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:41:44 PM 44 1374.50 TQEX
GENMAB A/S 28-Mar-25 12:41:44 PM 22 1374.50 AQEU
GENMAB A/S 28-Mar-25 12:41:45 PM 1 1374.50 XCSE

158

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:41:45 PM 1 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:42:28 PM 36 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:43:00 PM 10 1374.50 CEUX
GENMAB A/S 28-Mar-25 12:45:47 PM 78 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:15 PM 1 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:15 PM 36 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:48:17 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:48:28 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:48:35 PM 10 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:48:37 PM 35 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:37 PM 25 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:37 PM 10 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:37 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:48:37 PM 3 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:48:38 PM 1 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:50:00 PM 10 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:50:30 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:50:30 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:50:43 PM 1 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:00 PM 10 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:18 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:18 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:18 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:45 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:45 PM 6 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:51:45 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:45 PM 6 1374.00 CEUX
GENMAB A/S 28-Mar-25 12:51:52 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:52 PM 41 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:52 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:53 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:53 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:54 PM 7 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:54 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:54 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:55 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:55 PM 10 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:55 PM 30 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:55 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:56 PM 30 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:56 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:56 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:59 PM 74 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:51:59 PM 16 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:59 PM 30 1374.00 XCSE

159

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:51:59 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:59 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 12:51:59 PM 70 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:51:59 PM 35 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:51:59 PM 36 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:51:59 PM 30 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:51:59 PM 45 1373.50 TQEX
GENMAB A/S 28-Mar-25 12:51:59 PM 25 1373.00 AQEU
GENMAB A/S 28-Mar-25 12:52:00 PM 49 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:00 PM 11 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:00 PM 36 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:52:00 PM 6 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:52:00 PM 6 1373.00 CEUX
GENMAB A/S 28-Mar-25 12:52:00 PM 34 1373.50 CEUX
GENMAB A/S 28-Mar-25 12:52:02 PM 3 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:02 PM 42 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:04 PM 2 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:04 PM 30 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:04 PM 42 1373.00 XCSE
GENMAB A/S 28-Mar-25 12:52:14 PM 77 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:52:14 PM 101 1372.00 XCSE
GENMAB A/S 28-Mar-25 12:52:14 PM 79 1372.50 CEUX
GENMAB A/S 28-Mar-25 12:52:14 PM 37 1372.50 TQEX
GENMAB A/S 28-Mar-25 12:52:14 PM 19 1372.00 AQEU
GENMAB A/S 28-Mar-25 12:52:33 PM 76 1370.50 XCSE
GENMAB A/S 28-Mar-25 12:52:33 PM 45 1371.00 CEUX
GENMAB A/S 28-Mar-25 12:52:33 PM 34 1371.00 CEUX
GENMAB A/S 28-Mar-25 12:52:33 PM 32 1371.00 TQEX
GENMAB A/S 28-Mar-25 12:52:36 PM 79 1370.00 CEUX
GENMAB A/S 28-Mar-25 12:52:36 PM 42 1370.00 TQEX
GENMAB A/S 28-Mar-25 12:52:36 PM 28 1370.00 AQEU
GENMAB A/S 28-Mar-25 12:52:38 PM 46 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:52:38 PM 30 1369.50 XCSE
GENMAB A/S 28-Mar-25 12:54:59 PM 34 1370.00 CEUX
GENMAB A/S 28-Mar-25 12:54:59 PM 26 1370.00 CEUX
GENMAB A/S 28-Mar-25 12:55:00 PM 30 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:55:00 PM 8 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:55:00 PM 9 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:55:00 PM 3 1370.00 CEUX
GENMAB A/S 28-Mar-25 12:55:00 PM 15 1370.00 CEUX
GENMAB A/S 28-Mar-25 12:55:00 PM 16 1370.00 TQEX
GENMAB A/S 28-Mar-25 12:57:17 PM 79 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:57:17 PM 1 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:57:17 PM 9 1370.00 XCSE
GENMAB A/S 28-Mar-25 12:57:17 PM 42 1370.00 XCSE

160

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 12:57:17 PM 10 1370.00 TQEX
GENMAB A/S 28-Mar-25 12:57:45 PM 26 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:57:45 PM 10 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:57:46 PM 11 1371.00 XCSE
GENMAB A/S 28-Mar-25 12:57:48 PM 58 1371.00 XCSE
GENMAB A/S 28-Mar-25 1:00:07 PM 78 1370.00 CEUX
GENMAB A/S 28-Mar-25 1:01:17 PM 72 1369.50 XCSE
GENMAB A/S 28-Mar-25 1:02:46 PM 42 1369.50 XCSE
GENMAB A/S 28-Mar-25 1:02:46 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 1:02:46 PM 4 1369.50 XCSE
GENMAB A/S 28-Mar-25 1:02:46 PM 44 1369.50 XCSE
GENMAB A/S 28-Mar-25 1:02:46 PM 35 1369.50 AQEU
GENMAB A/S 28-Mar-25 1:05:17 PM 12 1369.50 CEUX
GENMAB A/S 28-Mar-25 1:05:18 PM 33 1369.50 CEUX
GENMAB A/S 28-Mar-25 1:05:18 PM 38 1369.50 CEUX
GENMAB A/S 28-Mar-25 1:05:29 PM 6 1369.00 CEUX
GENMAB A/S 28-Mar-25 1:05:43 PM 32 1369.00 CEUX
GENMAB A/S 28-Mar-25 1:06:13 PM 32 1369.00 CEUX
GENMAB A/S 28-Mar-25 1:06:35 PM 11 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:06:35 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:06:35 PM 5 1369.00 CEUX
GENMAB A/S 28-Mar-25 1:06:35 PM 16 1369.00 TQEX
GENMAB A/S 28-Mar-25 1:06:35 PM 6 1369.00 TQEX
GENMAB A/S 28-Mar-25 1:06:36 PM 15 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:06:36 PM 19 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:06:36 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 9 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 12 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 25 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 32 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 16 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 7 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 6 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 6 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 78 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 18 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:16 PM 3 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:37 PM 32 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:07:38 PM 33 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:38 PM 4 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:51 PM 12 1369.00 XCSE

161

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:07:51 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 1:07:54 PM 4 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:08:21 PM 42 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:08:21 PM 43 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:08:21 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:08:21 PM 1 1368.50 XCSE
GENMAB A/S 28-Mar-25 1:08:38 PM 32 1368.50 CEUX
GENMAB A/S 28-Mar-25 1:08:57 PM 14 1368.00 TQEX
GENMAB A/S 28-Mar-25 1:08:57 PM 13 1368.00 TQEX
GENMAB A/S 28-Mar-25 1:09:28 PM 28 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:09:28 PM 12 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:09:28 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:09:28 PM 30 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:11:19 PM 77 1367.50 XCSE
GENMAB A/S 28-Mar-25 1:11:19 PM 24 1367.50 XCSE
GENMAB A/S 28-Mar-25 1:11:19 PM 79 1367.50 CEUX
GENMAB A/S 28-Mar-25 1:14:17 PM 60 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:14:17 PM 41 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:14:17 PM 25 1367.00 TQEX
GENMAB A/S 28-Mar-25 1:16:27 PM 74 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:16:28 PM 15 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:16:28 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:16:28 PM 48 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:16:28 PM 35 1366.50 CEUX
GENMAB A/S 28-Mar-25 1:16:31 PM 9 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:16:31 PM 48 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:16:31 PM 44 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:16:31 PM 79 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:16:31 PM 42 1366.50 CEUX
GENMAB A/S 28-Mar-25 1:16:58 PM 10 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:17:18 PM 9 1368.00 XCSE
GENMAB A/S 28-Mar-25 1:17:18 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 1:17:18 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 1:17:39 PM 10 1368.00 XCSE
GENMAB A/S 28-Mar-25 1:17:39 PM 32 1368.00 XCSE
GENMAB A/S 28-Mar-25 1:17:39 PM 45 1367.50 XCSE
GENMAB A/S 28-Mar-25 1:17:39 PM 79 1368.00 XCSE
GENMAB A/S 28-Mar-25 1:17:39 PM 14 1367.50 XCSE
GENMAB A/S 28-Mar-25 1:17:39 PM 78 1367.50 CEUX
GENMAB A/S 28-Mar-25 1:17:39 PM 30 1367.50 TQEX
GENMAB A/S 28-Mar-25 1:17:40 PM 77 1367.00 XCSE
GENMAB A/S 28-Mar-25 1:17:41 PM 9 1366.50 CEUX
GENMAB A/S 28-Mar-25 1:18:47 PM 69 1366.50 CEUX
GENMAB A/S 28-Mar-25 1:18:47 PM 29 1366.50 TQEX
GENMAB A/S 28-Mar-25 1:20:10 PM 54 1366.50 CEUX

162

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:20:10 PM 22 1366.50 CEUX
GENMAB A/S 28-Mar-25 1:20:10 PM 22 1366.50 TQEX
GENMAB A/S 28-Mar-25 1:20:11 PM 75 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:20:11 PM 76 1365.50 CEUX
GENMAB A/S 28-Mar-25 1:20:11 PM 25 1366.00 AQEU
GENMAB A/S 28-Mar-25 1:20:13 PM 22 1365.00 AQEU
GENMAB A/S 28-Mar-25 1:23:39 PM 48 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:23:39 PM 30 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:23:39 PM 1 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:23:45 PM 8 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:24:35 PM 78 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:24:35 PM 28 1365.00 TQEX
GENMAB A/S 28-Mar-25 1:24:40 PM 18 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:24:40 PM 25 1365.00 AQEU
GENMAB A/S 28-Mar-25 1:24:41 PM 20 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:24:42 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:24:42 PM 48 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:25:08 PM 48 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:25:08 PM 1 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:25:08 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:25:08 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:25:19 PM 79 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:26:26 PM 13 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:26:26 PM 9 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:26:31 PM 31 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:26:51 PM 1 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:26:51 PM 4 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:27:46 PM 20 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:27:46 PM 34 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:27:46 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:27:46 PM 24 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:27:46 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:27:50 PM 31 1364.00 CEUX
GENMAB A/S 28-Mar-25 1:27:50 PM 43 1364.00 CEUX
GENMAB A/S 28-Mar-25 1:27:52 PM 20 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:28:43 PM 34 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:28:43 PM 18 1363.50 TQEX
GENMAB A/S 28-Mar-25 1:28:43 PM 4 1363.50 TQEX
GENMAB A/S 28-Mar-25 1:30:26 PM 11 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:30:26 PM 1 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:30:27 PM 25 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:30:27 PM 46 1363.00 CEUX
GENMAB A/S 28-Mar-25 1:30:27 PM 32 1363.00 CEUX
GENMAB A/S 28-Mar-25 1:30:29 PM 1 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:30:37 PM 5 1362.50 XCSE

163

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:30:37 PM 45 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:30:37 PM 23 1362.00 TQEX
GENMAB A/S 28-Mar-25 1:30:37 PM 1 1362.00 TQEX
GENMAB A/S 28-Mar-25 1:30:53 PM 12 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:30:54 PM 11 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:32:14 PM 27 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:32:19 PM 32 1363.00 TQEX
GENMAB A/S 28-Mar-25 1:32:25 PM 83 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:32:25 PM 48 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:32:26 PM 13 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:34:03 PM 12 1362.00 XCSE
GENMAB A/S 28-Mar-25 1:34:03 PM 47 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:03 PM 41 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:03 PM 48 1362.00 XCSE
GENMAB A/S 28-Mar-25 1:34:03 PM 11 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:34:03 PM 75 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:34:03 PM 12 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:34:31 PM 9 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:31 PM 13 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:41 PM 13 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:41 PM 12 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:34:41 PM 8 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:35:28 PM 14 1362.00 CEUX
GENMAB A/S 28-Mar-25 1:37:08 PM 13 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:08 PM 48 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:08 PM 76 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:08 PM 11 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:08 PM 18 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:37:08 PM 34 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:37:08 PM 24 1360.50 TQEX
GENMAB A/S 28-Mar-25 1:37:09 PM 12 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:37:23 PM 13 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:23 PM 11 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:23 PM 11 1361.50 XCSE
GENMAB A/S 28-Mar-25 1:37:23 PM 30 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:37:23 PM 32 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:37:46 PM 65 1362.00 XCSE
GENMAB A/S 28-Mar-25 1:37:46 PM 12 1362.00 XCSE
GENMAB A/S 28-Mar-25 1:37:46 PM 14 1362.00 AQEU
GENMAB A/S 28-Mar-25 1:37:46 PM 8 1362.00 AQEU
GENMAB A/S 28-Mar-25 1:38:53 PM 79 1362.00 XCSE
GENMAB A/S 28-Mar-25 1:38:53 PM 32 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:38:53 PM 47 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:38:53 PM 80 1361.50 CEUX
GENMAB A/S 28-Mar-25 1:38:53 PM 22 1362.00 TQEX

164

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:38:53 PM 23 1361.00 AQEU
GENMAB A/S 28-Mar-25 1:38:53 PM 28 1362.00 AQEU
GENMAB A/S 28-Mar-25 1:40:54 PM 12 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:40:54 PM 36 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:40:54 PM 13 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:40:54 PM 1 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:40:54 PM 39 1361.00 XCSE
GENMAB A/S 28-Mar-25 1:42:37 PM 23 1362.50 AQEU
GENMAB A/S 28-Mar-25 1:43:00 PM 34 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:00 PM 44 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:00 PM 25 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:43:00 PM 12 1362.50 TQEX
GENMAB A/S 28-Mar-25 1:43:25 PM 29 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:43:26 PM 13 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:26 PM 43 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:26 PM 7 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:26 PM 16 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:26 PM 10 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:43:26 PM 22 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:43:38 PM 26 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:43:41 PM 12 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:41 PM 43 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:43:41 PM 6 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:44:18 PM 3 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:44:18 PM 12 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:44:18 PM 2 1362.50 CEUX
GENMAB A/S 28-Mar-25 1:44:25 PM 1 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:44:25 PM 2 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:44:25 PM 1 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:44:45 PM 12 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:44:45 PM 8 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:44:51 PM 10 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:45:26 PM 5 1363.00 XCSE
GENMAB A/S 28-Mar-25 1:46:05 PM 31 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:05 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:05 PM 13 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:05 PM 2 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:05 PM 9 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:06 PM 14 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:06 PM 8 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:06 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:06 PM 1 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:06 PM 1 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:21 PM 11 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:21 PM 11 1363.50 XCSE

165

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:46:41 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:41 PM 9 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:41 PM 13 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:46:53 PM 25 1362.50 XCSE
GENMAB A/S 28-Mar-25 1:47:16 PM 5 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:16 PM 11 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:16 PM 24 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:16 PM 6 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:16 PM 17 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:17 PM 22 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:17 PM 17 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:17 PM 8 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:21 PM 5 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:47:21 PM 41 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:47:38 PM 1 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:47:38 PM 23 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:48:25 PM 7 1363.50 XCSE
GENMAB A/S 28-Mar-25 1:48:25 PM 10 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:49:25 PM 25 1363.50 CEUX
GENMAB A/S 28-Mar-25 1:50:09 PM 34 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:50:09 PM 15 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:50:09 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:50:09 PM 23 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:50:09 PM 13 1365.00 TQEX
GENMAB A/S 28-Mar-25 1:53:11 PM 34 1365.50 CEUX
GENMAB A/S 28-Mar-25 1:53:11 PM 1 1365.50 AQEU
GENMAB A/S 28-Mar-25 1:53:11 PM 21 1365.50 AQEU
GENMAB A/S 28-Mar-25 1:53:33 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:53:33 PM 15 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:53:33 PM 9 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:53:33 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:53:34 PM 7 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:00 PM 33 1366.00 TQEX
GENMAB A/S 28-Mar-25 1:54:12 PM 43 1365.50 CEUX
GENMAB A/S 28-Mar-25 1:54:14 PM 17 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:14 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:14 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:54:14 PM 6 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:54:14 PM 80 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:54:15 PM 36 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:15 PM 14 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:26 PM 41 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:26 PM 23 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:26 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:26 PM 10 1366.00 XCSE

166

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 1:54:27 PM 26 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:54:27 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 1 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 3 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:00 PM 42 1366.50 XCSE
GENMAB A/S 28-Mar-25 1:55:19 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:55:31 PM 19 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:55:31 PM 44 1366.00 XCSE
GENMAB A/S 28-Mar-25 1:55:31 PM 24 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:55:31 PM 51 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:55:31 PM 43 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:55:31 PM 79 1366.00 CEUX
GENMAB A/S 28-Mar-25 1:55:31 PM 3 1366.00 TQEX
GENMAB A/S 28-Mar-25 1:55:31 PM 33 1366.00 TQEX
GENMAB A/S 28-Mar-25 1:55:31 PM 29 1366.00 TQEX
GENMAB A/S 28-Mar-25 1:56:57 PM 36 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:56:57 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:56:57 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:56:57 PM 5 1365.50 AQEU
GENMAB A/S 28-Mar-25 1:56:58 PM 100 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:56:58 PM 14 1365.50 XCSE
GENMAB A/S 28-Mar-25 1:57:19 PM 80 1365.00 CEUX
GENMAB A/S 28-Mar-25 1:57:41 PM 8 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:57:41 PM 41 1365.00 XCSE
GENMAB A/S 28-Mar-25 1:58:46 PM 76 1364.50 XCSE
GENMAB A/S 28-Mar-25 1:58:46 PM 23 1365.00 TQEX
GENMAB A/S 28-Mar-25 1:58:46 PM 6 1364.50 AQEU
GENMAB A/S 28-Mar-25 1:58:48 PM 21 1365.50 AQEU
GENMAB A/S 28-Mar-25 2:00:55 PM 42 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:00:55 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:00:55 PM 18 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:00:55 PM 30 1367.50 AQEU
GENMAB A/S 28-Mar-25 2:01:28 PM 40 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:01:28 PM 53 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:01:28 PM 8 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:01:45 PM 25 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:02:05 PM 42 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:02:05 PM 13 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:02:05 PM 30 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:02:36 PM 74 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:03:08 PM 11 1367.00 CEUX

167

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:03:08 PM 1 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:03:28 PM 10 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:03:28 PM 12 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:04:25 PM 32 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:04:35 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:35 PM 20 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:35 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:45 PM 20 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:45 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:45 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:04:45 PM 78 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:04:45 PM 27 1366.50 TQEX
GENMAB A/S 28-Mar-25 2:05:12 PM 30 1366.50 AQEU
GENMAB A/S 28-Mar-25 2:05:21 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:21 PM 31 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:51 PM 23 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:51 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:51 PM 10 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:51 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:05:51 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:06:41 PM 75 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:06:41 PM 34 1365.00 XCSE
GENMAB A/S 28-Mar-25 2:06:41 PM 78 1365.00 XCSE
GENMAB A/S 28-Mar-25 2:06:41 PM 74 1365.50 CEUX
GENMAB A/S 28-Mar-25 2:06:41 PM 20 1364.00 CEUX
GENMAB A/S 28-Mar-25 2:06:41 PM 14 1364.00 CEUX
GENMAB A/S 28-Mar-25 2:06:41 PM 24 1365.50 TQEX
GENMAB A/S 28-Mar-25 2:06:41 PM 2 1365.00 TQEX
GENMAB A/S 28-Mar-25 2:06:41 PM 23 1365.00 AQEU
GENMAB A/S 28-Mar-25 2:06:41 PM 2 1364.00 AQEU
GENMAB A/S 28-Mar-25 2:06:41 PM 2 1366.50 AQEU
GENMAB A/S 28-Mar-25 2:06:41 PM 23 1365.50 AQEU
GENMAB A/S 28-Mar-25 2:06:41 PM 29 1364.00 AQEU
GENMAB A/S 28-Mar-25 2:07:46 PM 4 1364.00 CEUX
GENMAB A/S 28-Mar-25 2:08:37 PM 34 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:08:37 PM 43 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:09:47 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:09:47 PM 22 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:09:47 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:04 PM 72 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:11:04 PM 4 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:11:04 PM 29 1366.50 TQEX
GENMAB A/S 28-Mar-25 2:11:04 PM 29 1366.50 AQEU
GENMAB A/S 28-Mar-25 2:11:05 PM 44 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:11:31 PM 23 1367.00 XCSE

168

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:11:31 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:31 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:31 PM 14 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:31 PM 24 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:32 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:32 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:32 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:32 PM 24 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:11:32 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:12:11 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:12:11 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:13:25 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:13:25 PM 32 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:13:58 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 42 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 2 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 26 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 75 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:13:58 PM 80 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:13:58 PM 23 1366.50 TQEX
GENMAB A/S 28-Mar-25 2:13:58 PM 29 1366.50 AQEU
GENMAB A/S 28-Mar-25 2:14:13 PM 20 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:14:13 PM 43 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:14:51 PM 47 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:15:25 PM 21 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:15:25 PM 1 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:15:41 PM 43 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:15:41 PM 6 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:15:41 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:16:00 PM 21 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:16:00 PM 55 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:16:25 PM 3 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:16:26 PM 14 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:16:47 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:16:47 PM 11 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:16:47 PM 11 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:17:01 PM 74 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:17:04 PM 22 1366.50 TQEX
GENMAB A/S 28-Mar-25 2:17:28 PM 9 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:17:28 PM 56 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:17:28 PM 36 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:17:50 PM 26 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:17:50 PM 52 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:18:25 PM 11 1366.00 XCSE

169

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:18:25 PM 24 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:18:25 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:18:27 PM 37 1365.00 XCSE
GENMAB A/S 28-Mar-25 2:18:27 PM 20 1364.50 XCSE
GENMAB A/S 28-Mar-25 2:18:27 PM 79 1365.50 XCSE
GENMAB A/S 28-Mar-25 2:18:27 PM 65 1365.00 CEUX
GENMAB A/S 28-Mar-25 2:18:27 PM 14 1365.00 CEUX
GENMAB A/S 28-Mar-25 2:18:27 PM 30 1365.00 TQEX
GENMAB A/S 28-Mar-25 2:18:27 PM 22 1365.50 AQEU
GENMAB A/S 28-Mar-25 2:18:37 PM 44 1364.50 XCSE
GENMAB A/S 28-Mar-25 2:18:37 PM 10 1364.50 XCSE
GENMAB A/S 28-Mar-25 2:18:37 PM 27 1364.50 AQEU
GENMAB A/S 28-Mar-25 2:18:39 PM 34 1364.00 CEUX
GENMAB A/S 28-Mar-25 2:19:09 PM 6 1364.00 CEUX
GENMAB A/S 28-Mar-25 2:19:16 PM 76 1363.50 XCSE
GENMAB A/S 28-Mar-25 2:19:16 PM 22 1363.50 TQEX
GENMAB A/S 28-Mar-25 2:22:27 PM 74 1365.50 XCSE
GENMAB A/S 28-Mar-25 2:23:25 PM 46 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:23:25 PM 34 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:23:43 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:23:43 PM 67 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:23:43 PM 78 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:23:43 PM 31 1367.00 TQEX
GENMAB A/S 28-Mar-25 2:23:43 PM 17 1367.00 AQEU
GENMAB A/S 28-Mar-25 2:23:43 PM 3 1367.00 AQEU
GENMAB A/S 28-Mar-25 2:23:43 PM 7 1367.00 AQEU
GENMAB A/S 28-Mar-25 2:24:00 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:24:30 PM 14 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:24:30 PM 30 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:24:30 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:25:26 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:25:48 PM 12 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:25:48 PM 10 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:25:48 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:25:48 PM 29 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:26:17 PM 79 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:26:23 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:26:23 PM 14 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:27:50 PM 32 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:27:50 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:27:50 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:27:50 PM 5 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:27:50 PM 29 1367.50 CEUX
GENMAB A/S 28-Mar-25 2:27:50 PM 37 1367.50 CEUX
GENMAB A/S 28-Mar-25 2:27:50 PM 30 1367.50 CEUX

170

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:27:50 PM 41 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:27:50 PM 5 1367.50 CEUX
GENMAB A/S 28-Mar-25 2:27:50 PM 34 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:27:50 PM 22 1367.00 TQEX
GENMAB A/S 28-Mar-25 2:27:50 PM 22 1367.00 AQEU
GENMAB A/S 28-Mar-25 2:28:25 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:25 PM 76 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:25 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:28:25 PM 42 1366.50 XCSE
GENMAB A/S 28-Mar-25 2:28:25 PM 10 1366.00 AQEU
GENMAB A/S 28-Mar-25 2:28:41 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:41 PM 29 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:41 PM 30 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:41 PM 25 1366.00 TQEX
GENMAB A/S 28-Mar-25 2:28:41 PM 14 1366.00 AQEU
GENMAB A/S 28-Mar-25 2:28:44 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:44 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:44 PM 21 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:44 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:28:48 PM 32 1366.00 CEUX
GENMAB A/S 28-Mar-25 2:29:05 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:29:05 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 10 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 7 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 42 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 26 1367.00 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 16 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:30:00 PM 10 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 30 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 34 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 11 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 2 1366.50 CEUX
GENMAB A/S 28-Mar-25 2:30:00 PM 10 1367.00 CEUX
GENMAB A/S 28-Mar-25 2:30:01 PM 101 1367.50 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 3 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:20 PM 5 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:29 PM 16 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:30:29 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:30:29 PM 7 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:30:29 PM 12 1368.50 XCSE

171

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:30:29 PM 42 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:30:37 PM 30 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:37 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 5 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 10 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:30:38 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:31:12 PM 75 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:31:12 PM 75 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:12 PM 36 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:12 PM 10 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:12 PM 11 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:12 PM 33 1370.50 TQEX
GENMAB A/S 28-Mar-25 2:31:12 PM 22 1370.50 AQEU
GENMAB A/S 28-Mar-25 2:31:16 PM 42 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:31:16 PM 20 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:16 PM 36 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:31:16 PM 2 1370.50 TQEX
GENMAB A/S 28-Mar-25 2:31:16 PM 22 1370.50 TQEX
GENMAB A/S 28-Mar-25 2:31:16 PM 34 1370.50 AQEU
GENMAB A/S 28-Mar-25 2:31:26 PM 2 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:31:31 PM 46 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:31:31 PM 24 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:31:47 PM 20 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:32:17 PM 62 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:32:17 PM 14 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:32:17 PM 15 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:32:17 PM 36 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:32:25 PM 18 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:32:49 PM 44 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:32:49 PM 80 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:32:49 PM 3 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:32:49 PM 36 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:32:49 PM 29 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:32:49 PM 48 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:32:49 PM 22 1371.50 TQEX
GENMAB A/S 28-Mar-25 2:32:49 PM 31 1371.50 AQEU
GENMAB A/S 28-Mar-25 2:33:05 PM 8 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:33:05 PM 14 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:33:05 PM 32 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:33:09 PM 42 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:33:09 PM 12 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 17 1371.00 XCSE

172

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:33:24 PM 12 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 64 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 42 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 10 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 30 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:33:24 PM 74 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:33:24 PM 28 1370.50 TQEX
GENMAB A/S 28-Mar-25 2:33:27 PM 79 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:33:40 PM 78 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:33:59 PM 30 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:33:59 PM 25 1370.50 TQEX
GENMAB A/S 28-Mar-25 2:34:17 PM 75 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:34:17 PM 76 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:34:17 PM 34 1369.50 TQEX
GENMAB A/S 28-Mar-25 2:34:38 PM 27 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:34:38 PM 1 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:34:38 PM 22 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:35:25 PM 3 1370.00 CEUX
GENMAB A/S 28-Mar-25 2:35:25 PM 30 1370.00 CEUX
GENMAB A/S 28-Mar-25 2:35:26 PM 3 1370.00 CEUX
GENMAB A/S 28-Mar-25 2:35:26 PM 58 1370.00 CEUX
GENMAB A/S 28-Mar-25 2:35:35 PM 78 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:35:35 PM 22 1369.50 TQEX
GENMAB A/S 28-Mar-25 2:35:42 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 14 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 50 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 9 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 19 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 42 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:42 PM 76 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:35:51 PM 42 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:35:51 PM 1 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:35:51 PM 18 1368.50 AQEU
GENMAB A/S 28-Mar-25 2:35:51 PM 4 1368.50 AQEU
GENMAB A/S 28-Mar-25 2:35:57 PM 4 1368.50 XCSE
GENMAB A/S 28-Mar-25 2:35:57 PM 1 1368.50 AQEU
GENMAB A/S 28-Mar-25 2:36:01 PM 75 1368.00 XCSE
GENMAB A/S 28-Mar-25 2:36:01 PM 80 1368.00 CEUX
GENMAB A/S 28-Mar-25 2:36:12 PM 25 1368.00 TQEX
GENMAB A/S 28-Mar-25 2:38:27 PM 62 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:38:32 PM 35 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:38:33 PM 30 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:38:33 PM 14 1371.00 CEUX

173

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:38:56 PM 38 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:38:56 PM 10 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:38:56 PM 13 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:39:19 PM 38 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:39:19 PM 15 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:40:47 PM 36 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:40:47 PM 78 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:40:47 PM 26 1373.00 AQEU
GENMAB A/S 28-Mar-25 2:41:07 PM 23 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:07 PM 54 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:07 PM 36 1372.50 TQEX
GENMAB A/S 28-Mar-25 2:41:08 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:08 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:08 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:08 PM 5 1372.50 CEUX
GENMAB A/S 28-Mar-25 2:41:08 PM 6 1372.50 CEUX
GENMAB A/S 28-Mar-25 2:41:08 PM 36 1372.50 CEUX
GENMAB A/S 28-Mar-25 2:41:09 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:09 PM 4 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:09 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:41:09 PM 61 1372.50 CEUX
GENMAB A/S 28-Mar-25 2:42:01 PM 76 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:05 PM 62 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:05 PM 36 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:06 PM 36 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:06 PM 5 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:14 PM 36 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:15 PM 16 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:15 PM 32 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:42:26 PM 13 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:26 PM 13 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:26 PM 44 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:26 PM 11 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:26 PM 11 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:42:28 PM 54 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:43:16 PM 74 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:43:22 PM 78 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:43:22 PM 5 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:43:22 PM 80 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:43:22 PM 39 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:43:22 PM 11 1371.00 TQEX
GENMAB A/S 28-Mar-25 2:43:22 PM 49 1372.00 TQEX
GENMAB A/S 28-Mar-25 2:43:22 PM 41 1371.00 TQEX
GENMAB A/S 28-Mar-25 2:43:22 PM 3 1371.00 TQEX
GENMAB A/S 28-Mar-25 2:43:22 PM 11 1371.00 TQEX

174

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:43:35 PM 74 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:44:50 PM 24 1372.50 TQEX
GENMAB A/S 28-Mar-25 2:44:58 PM 60 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:44:58 PM 19 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:44:58 PM 75 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:44:58 PM 77 1372.00 CEUX
GENMAB A/S 28-Mar-25 2:44:58 PM 23 1372.00 AQEU
GENMAB A/S 28-Mar-25 2:44:59 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:44:59 PM 64 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:44:59 PM 15 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 15 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 30 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 42 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 6 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 13 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:00 PM 12 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:45:01 PM 77 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:01 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:01 PM 30 1371.00 CEUX
GENMAB A/S 28-Mar-25 2:45:01 PM 22 1371.50 TQEX
GENMAB A/S 28-Mar-25 2:45:02 PM 11 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 12 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 42 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 22 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 13 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 42 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 16 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 11 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 12 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:02 PM 13 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:07 PM 3 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:45:11 PM 22 1370.00 AQEU
GENMAB A/S 28-Mar-25 2:45:26 PM 3 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:26 PM 1 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:45:29 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:29 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:29 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:30 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:30 PM 101 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:45:55 PM 39 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:55 PM 4 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:55 PM 16 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:55 PM 42 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 12 1372.50 XCSE

175

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:45:56 PM 20 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 16 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 2 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 42 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 11 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 13 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 50 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:45:56 PM 24 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:46:36 PM 12 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:46:36 PM 2 1372.50 XCSE
GENMAB A/S 28-Mar-25 2:46:53 PM 41 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:46:53 PM 75 1371.00 XCSE
GENMAB A/S 28-Mar-25 2:46:53 PM 75 1372.00 XCSE
GENMAB A/S 28-Mar-25 2:46:53 PM 60 1371.50 XCSE
GENMAB A/S 28-Mar-25 2:46:53 PM 74 1371.50 CEUX
GENMAB A/S 28-Mar-25 2:46:53 PM 22 1371.50 TQEX
GENMAB A/S 28-Mar-25 2:47:01 PM 13 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:47:01 PM 77 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:47:01 PM 50 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:47:01 PM 38 1370.50 XCSE
GENMAB A/S 28-Mar-25 2:47:01 PM 34 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:47:01 PM 45 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:47:01 PM 31 1370.00 TQEX
GENMAB A/S 28-Mar-25 2:47:56 PM 101 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 78 1370.00 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 21 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 30 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 9 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:47:56 PM 54 1369.50 CEUX
GENMAB A/S 28-Mar-25 2:47:56 PM 77 1370.50 CEUX
GENMAB A/S 28-Mar-25 2:47:57 PM 30 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:47:57 PM 12 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:47:57 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:47:57 PM 41 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:47:57 PM 5 1369.00 XCSE
GENMAB A/S 28-Mar-25 2:48:58 PM 29 1369.00 CEUX
GENMAB A/S 28-Mar-25 2:48:58 PM 11 1369.00 CEUX
GENMAB A/S 28-Mar-25 2:49:27 PM 74 1369.50 XCSE
GENMAB A/S 28-Mar-25 2:50:54 PM 74 1374.00 XCSE
GENMAB A/S 28-Mar-25 2:50:54 PM 16 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:50:54 PM 42 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:50:54 PM 32 1373.50 TQEX
GENMAB A/S 28-Mar-25 2:51:07 PM 5 1373.50 XCSE

176

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:51:07 PM 30 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 43 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 21 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 50 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 77 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:07 PM 76 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:51:08 PM 8 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:08 PM 17 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:51:08 PM 12 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:00 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:00 PM 30 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:00 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:00 PM 64 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:52:00 PM 12 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:52:00 PM 22 1373.50 TQEX
GENMAB A/S 28-Mar-25 2:52:08 PM 13 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:08 PM 24 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:08 PM 12 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:09 PM 9 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:52:09 PM 13 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:52:09 PM 77 1373.00 CEUX
GENMAB A/S 28-Mar-25 2:52:09 PM 22 1373.00 AQEU
GENMAB A/S 28-Mar-25 2:52:21 PM 41 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:52:41 PM 14 1373.00 XCSE
GENMAB A/S 28-Mar-25 2:52:53 PM 33 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:53 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:53 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:52:53 PM 12 1373.50 XCSE
GENMAB A/S 28-Mar-25 2:54:03 PM 74 1374.00 CEUX
GENMAB A/S 28-Mar-25 2:54:03 PM 22 1374.00 AQEU
GENMAB A/S 28-Mar-25 2:54:04 PM 4 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 61 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 26 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 40 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 12 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 42 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:04 PM 11 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:31 PM 13 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:54:31 PM 13 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:55:21 PM 69 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:55:21 PM 32 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:55:22 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:55:25 PM 8 1374.50 TQEX

177

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 2:55:32 PM 12 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:56:27 PM 2 1375.50 CEUX
GENMAB A/S 28-Mar-25 2:56:38 PM 9 1375.00 AQEU
GENMAB A/S 28-Mar-25 2:57:25 PM 37 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:57:25 PM 5 1375.50 XCSE
GENMAB A/S 28-Mar-25 2:57:25 PM 18 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:57:25 PM 10 1374.50 XCSE
GENMAB A/S 28-Mar-25 2:57:25 PM 20 1375.50 CEUX
GENMAB A/S 28-Mar-25 2:57:25 PM 13 1375.00 AQEU
GENMAB A/S 28-Mar-25 2:57:25 PM 8 1374.00 AQEU
GENMAB A/S 28-Mar-25 2:58:13 PM 25 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:58:13 PM 53 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:58:13 PM 8 1375.00 XCSE
GENMAB A/S 28-Mar-25 2:58:25 PM 29 1376.00 CEUX
GENMAB A/S 28-Mar-25 2:58:25 PM 10 1376.00 CEUX
GENMAB A/S 28-Mar-25 2:58:25 PM 21 1376.00 CEUX
GENMAB A/S 28-Mar-25 2:58:40 PM 40 1376.00 XCSE
GENMAB A/S 28-Mar-25 2:59:02 PM 15 1375.50 CEUX
GENMAB A/S 28-Mar-25 2:59:02 PM 78 1375.50 CEUX
GENMAB A/S 28-Mar-25 2:59:02 PM 41 1375.50 TQEX
GENMAB A/S 28-Mar-25 2:59:25 PM 2 1375.50 XCSE
GENMAB A/S 28-Mar-25 2:59:26 PM 7 1375.50 CEUX
GENMAB A/S 28-Mar-25 2:59:59 PM 10 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 16 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 9 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 55 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 13 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 2 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 1 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 4 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 6 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 7 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 2 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 10 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 69 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 31 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:00:00 PM 26 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 38 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 13 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 2 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 20 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 29 1373.00 CEUX

178

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 7 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 6 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 5 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 15 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:00:00 PM 6 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 16 1374.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 8 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 5 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 2 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:00:00 PM 15 1374.00 AQEU
GENMAB A/S 28-Mar-25 3:00:00 PM 7 1373.00 AQEU
GENMAB A/S 28-Mar-25 3:00:00 PM 3 1373.00 AQEU
GENMAB A/S 28-Mar-25 3:00:25 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:00:25 PM 5 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:00:26 PM 31 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:00:28 PM 1 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:00:28 PM 4 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:01:03 PM 78 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:01:03 PM 80 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:01:03 PM 31 1374.00 TQEX
GENMAB A/S 28-Mar-25 3:01:03 PM 10 1373.00 AQEU
GENMAB A/S 28-Mar-25 3:01:38 PM 3 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:01:38 PM 5 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:01:38 PM 2 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:01:38 PM 14 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:01:38 PM 1 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:01:38 PM 73 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:01:38 PM 8 1373.00 AQEU
GENMAB A/S 28-Mar-25 3:02:17 PM 54 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:02:26 PM 10 1372.50 TQEX
GENMAB A/S 28-Mar-25 3:02:26 PM 17 1372.50 TQEX
GENMAB A/S 28-Mar-25 3:03:12 PM 76 1372.00 CEUX
GENMAB A/S 28-Mar-25 3:03:12 PM 36 1372.50 CEUX
GENMAB A/S 28-Mar-25 3:03:12 PM 6 1372.50 CEUX
GENMAB A/S 28-Mar-25 3:04:07 PM 80 1371.50 XCSE
GENMAB A/S 28-Mar-25 3:04:17 PM 14 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:17 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:17 PM 34 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:17 PM 42 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 32 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 53 1372.00 XCSE

179

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:04:18 PM 10 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 13 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 16 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 20 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:18 PM 12 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:19 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:19 PM 11 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:19 PM 20 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:04:28 PM 14 1372.00 CEUX
GENMAB A/S 28-Mar-25 3:04:28 PM 7 1372.00 CEUX
GENMAB A/S 28-Mar-25 3:04:28 PM 29 1372.00 CEUX
GENMAB A/S 28-Mar-25 3:04:28 PM 12 1372.00 CEUX
GENMAB A/S 28-Mar-25 3:06:02 PM 62 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:06:47 PM 62 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:07:01 PM 17 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:07:30 PM 20 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:07:30 PM 41 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:07:55 PM 37 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:07:56 PM 13 1374.50 XCSE
GENMAB A/S 28-Mar-25 3:07:56 PM 12 1374.50 XCSE
GENMAB A/S 28-Mar-25 3:07:56 PM 14 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:07:57 PM 10 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:07:57 PM 65 1374.00 CEUX
GENMAB A/S 28-Mar-25 3:07:57 PM 23 1374.00 AQEU
GENMAB A/S 28-Mar-25 3:08:00 PM 40 1375.00 CEUX
GENMAB A/S 28-Mar-25 3:08:48 PM 10 1375.00 CEUX
GENMAB A/S 28-Mar-25 3:09:00 PM 11 1375.00 CEUX
GENMAB A/S 28-Mar-25 3:09:47 PM 36 1375.50 XCSE
GENMAB A/S 28-Mar-25 3:10:13 PM 40 1375.50 XCSE
GENMAB A/S 28-Mar-25 3:10:13 PM 1 1375.50 XCSE
GENMAB A/S 28-Mar-25 3:10:13 PM 15 1375.50 XCSE
GENMAB A/S 28-Mar-25 3:10:13 PM 58 1375.50 CEUX
GENMAB A/S 28-Mar-25 3:10:13 PM 36 1375.50 CEUX
GENMAB A/S 28-Mar-25 3:10:13 PM 21 1375.50 CEUX
GENMAB A/S 28-Mar-25 3:10:13 PM 15 1375.50 CEUX
GENMAB A/S 28-Mar-25 3:10:13 PM 37 1375.50 TQEX
GENMAB A/S 28-Mar-25 3:10:14 PM 10 1375.50 CEUX
GENMAB A/S 28-Mar-25 3:10:42 PM 76 1376.00 CEUX
GENMAB A/S 28-Mar-25 3:10:42 PM 28 1376.00 TQEX
GENMAB A/S 28-Mar-25 3:10:52 PM 38 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 13 1375.00 XCSE

180

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:10:52 PM 6 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 42 1374.50 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 38 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 30 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 12 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 74 1374.50 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 4 1375.00 XCSE
GENMAB A/S 28-Mar-25 3:10:52 PM 2 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 59 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 6 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 4 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 16 1374.50 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 7 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:52 PM 31 1374.50 TQEX
GENMAB A/S 28-Mar-25 3:10:52 PM 20 1373.50 TQEX
GENMAB A/S 28-Mar-25 3:10:52 PM 20 1373.50 AQEU
GENMAB A/S 28-Mar-25 3:10:52 PM 25 1376.00 AQEU
GENMAB A/S 28-Mar-25 3:10:52 PM 2 1373.50 AQEU
GENMAB A/S 28-Mar-25 3:10:53 PM 3 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:53 PM 3 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:53 PM 53 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:10:53 PM 1 1373.00 CEUX
GENMAB A/S 28-Mar-25 3:11:00 PM 30 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:11:00 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:11:00 PM 42 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:11:00 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:11:00 PM 11 1373.50 XCSE
GENMAB A/S 28-Mar-25 3:11:00 PM 77 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:11:18 PM 5 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 16 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 19 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:35 PM 17 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:11:35 PM 6 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:11:35 PM 30 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:11:35 PM 20 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:11:35 PM 25 1373.50 AQEU
GENMAB A/S 28-Mar-25 3:11:36 PM 15 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 15 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 5 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 13 1374.00 XCSE

181

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:11:36 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 3 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 14 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 30 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:36 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 9 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 4 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 3 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:37 PM 5 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 2 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 19 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 6 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 16 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:55 PM 23 1373.50 AQEU
GENMAB A/S 28-Mar-25 3:11:56 PM 13 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:56 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:56 PM 11 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:56 PM 12 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:11:56 PM 42 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:12:03 PM 2 1374.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 60 1372.50 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 8 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 1 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 13 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 66 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 76 1372.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 20 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 4 1373.00 XCSE
GENMAB A/S 28-Mar-25 3:12:27 PM 23 1373.50 CEUX
GENMAB A/S 28-Mar-25 3:12:27 PM 74 1372.50 CEUX
GENMAB A/S 28-Mar-25 3:12:27 PM 22 1372.50 TQEX
GENMAB A/S 28-Mar-25 3:12:55 PM 64 1371.50 CEUX
GENMAB A/S 28-Mar-25 3:12:55 PM 12 1371.50 CEUX

182

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:13:10 PM 80 1371.00 XCSE
GENMAB A/S 28-Mar-25 3:13:10 PM 42 1371.00 XCSE
GENMAB A/S 28-Mar-25 3:13:10 PM 17 1371.00 XCSE
GENMAB A/S 28-Mar-25 3:13:15 PM 79 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:13:15 PM 17 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:13:15 PM 53 1370.00 CEUX
GENMAB A/S 28-Mar-25 3:14:21 PM 80 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:14:21 PM 27 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:14:21 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:15:00 PM 43 1370.50 TQEX
GENMAB A/S 28-Mar-25 3:15:28 PM 2 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:16:21 PM 1 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:16:37 PM 75 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:16:37 PM 1 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:16:42 PM 101 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:16:42 PM 74 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:16:42 PM 22 1370.00 AQEU
GENMAB A/S 28-Mar-25 3:16:43 PM 101 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:16:43 PM 42 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:16:43 PM 59 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:16:43 PM 80 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:16:53 PM 40 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:16:53 PM 22 1369.50 TQEX
GENMAB A/S 28-Mar-25 3:16:58 PM 74 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:16:58 PM 23 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:16:58 PM 25 1368.50 AQEU
GENMAB A/S 28-Mar-25 3:17:10 PM 12 1368.50 AQEU
GENMAB A/S 28-Mar-25 3:17:10 PM 10 1368.50 AQEU
GENMAB A/S 28-Mar-25 3:17:47 PM 35 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:17:47 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:17:47 PM 35 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:17:47 PM 16 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:18:54 PM 50 1368.50 CEUX
GENMAB A/S 28-Mar-25 3:18:54 PM 22 1368.50 AQEU
GENMAB A/S 28-Mar-25 3:18:56 PM 15 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:18:56 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:18:56 PM 30 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:18:56 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:18:56 PM 80 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:18:56 PM 14 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:21:12 PM 73 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:21:12 PM 2 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:21:12 PM 75 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:21:12 PM 22 1369.50 TQEX
GENMAB A/S 28-Mar-25 3:21:25 PM 12 1369.50 XCSE

183

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:21:26 PM 6 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:22:27 PM 53 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:22:30 PM 4 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:23:10 PM 28 1370.00 TQEX
GENMAB A/S 28-Mar-25 3:24:37 PM 74 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:24:42 PM 11 1370.00 AQEU
GENMAB A/S 28-Mar-25 3:25:10 PM 30 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:25:10 PM 11 1370.00 AQEU
GENMAB A/S 28-Mar-25 3:25:43 PM 9 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:25:57 PM 71 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:25:57 PM 36 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:25:57 PM 34 1370.50 AQEU
GENMAB A/S 28-Mar-25 3:26:25 PM 13 1371.00 XCSE
GENMAB A/S 28-Mar-25 3:26:25 PM 6 1371.00 CEUX
GENMAB A/S 28-Mar-25 3:26:28 PM 6 1371.00 CEUX
GENMAB A/S 28-Mar-25 3:27:26 PM 22 1371.00 CEUX
GENMAB A/S 28-Mar-25 3:27:50 PM 3 1371.00 XCSE
GENMAB A/S 28-Mar-25 3:27:50 PM 11 1371.00 CEUX
GENMAB A/S 28-Mar-25 3:28:29 PM 24 1371.00 TQEX
GENMAB A/S 28-Mar-25 3:28:29 PM 13 1371.00 TQEX
GENMAB A/S 28-Mar-25 3:28:38 PM 61 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:28:38 PM 15 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:29:26 PM 12 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:30:43 PM 34 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:30:43 PM 16 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:30:47 PM 20 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:30:59 PM 13 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 42 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 22 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 35 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 4 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 44 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 20 1370.50 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 79 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:30:59 PM 7 1370.50 CEUX
GENMAB A/S 28-Mar-25 3:30:59 PM 46 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:30:59 PM 25 1370.00 TQEX
GENMAB A/S 28-Mar-25 3:31:00 PM 12 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 11 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 20 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 20 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 12 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 12 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 42 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 12 1370.00 XCSE

184

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:31:00 PM 12 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 13 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:00 PM 21 1369.50 TQEX
GENMAB A/S 28-Mar-25 3:31:00 PM 3 1369.50 TQEX
GENMAB A/S 28-Mar-25 3:31:01 PM 42 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:01 PM 13 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:01 PM 19 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:01 PM 42 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:01 PM 11 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:01 PM 13 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:02 PM 5 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:02 PM 11 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:22 PM 12 1370.00 XCSE
GENMAB A/S 28-Mar-25 3:31:30 PM 31 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:30 PM 45 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:30 PM 27 1369.50 TQEX
GENMAB A/S 28-Mar-25 3:31:31 PM 2 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 30 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:47 PM 36 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:47 PM 6 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:47 PM 5 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:51 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:51 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:51 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:52 PM 3 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:52 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:52 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:53 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:55 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:55 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:55 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:55 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:55 PM 12 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:31:56 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 41 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 11 1369.50 XCSE

185

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:31:56 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:56 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:57 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:31:58 PM 13 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:32:08 PM 10 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:32:08 PM 15 1369.50 CEUX
GENMAB A/S 28-Mar-25 3:32:10 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:32:10 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:32:11 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:32:11 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:32:18 PM 7 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:32:32 PM 52 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:32:32 PM 6 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:32:32 PM 17 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:32:32 PM 69 1368.50 CEUX
GENMAB A/S 28-Mar-25 3:32:32 PM 42 1368.50 TQEX
GENMAB A/S 28-Mar-25 3:33:13 PM 23 1368.00 AQEU
GENMAB A/S 28-Mar-25 3:33:26 PM 35 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:33:26 PM 1 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:33:27 PM 4 1368.50 XCSE
GENMAB A/S 28-Mar-25 3:33:27 PM 73 1368.50 XCSE
GENMAB A/S 28-Mar-25 3:33:28 PM 2 1368.50 XCSE
GENMAB A/S 28-Mar-25 3:33:29 PM 20 1368.50 XCSE
GENMAB A/S 28-Mar-25 3:33:48 PM 53 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:09 PM 24 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:09 PM 78 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:34:25 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 20 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 44 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 25 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 3 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:25 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:34:28 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:34:28 PM 11 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:34:28 PM 78 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:34:37 PM 20 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:34:37 PM 3 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:34:37 PM 10 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:34:48 PM 20 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:34:48 PM 20 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:34:51 PM 4 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:36:00 PM 36 1369.00 XCSE

186

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:36:00 PM 43 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:36:15 PM 4 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:36:15 PM 1 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:36:20 PM 75 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:36:28 PM 12 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:36:28 PM 65 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:36:28 PM 11 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:36:28 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 3:36:28 PM 39 1369.50 XCSE
GENMAB A/S 28-Mar-25 3:37:38 PM 23 1368.50 TQEX
GENMAB A/S 28-Mar-25 3:37:47 PM 76 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:18 PM 75 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:38:18 PM 5 1369.00 CEUX
GENMAB A/S 28-Mar-25 3:38:31 PM 50 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:38:31 PM 24 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:38:38 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:38 PM 9 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:38 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:39 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:40 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:41 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 33 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:42 PM 33 1368.00 XCSE

187

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:38:42 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:51 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:38:51 PM 8 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:39:11 PM 2 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:39:11 PM 15 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:39:11 PM 53 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:39:17 PM 80 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:40:27 PM 46 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:41:05 PM 34 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:41:05 PM 35 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:41:05 PM 8 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:41:07 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:41:08 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:41:38 PM 6 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:41:38 PM 6 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:43:01 PM 30 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:43:01 PM 45 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:43:01 PM 25 1367.00 TQEX
GENMAB A/S 28-Mar-25 3:43:14 PM 23 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:43:26 PM 54 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:43:26 PM 20 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:43:26 PM 1 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:43:57 PM 44 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:05 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:05 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:05 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:06 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:10 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:10 PM 42 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:42 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:44:42 PM 36 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:45:34 PM 35 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:45:34 PM 41 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:45:44 PM 16 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:44 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:45 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:45 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 39 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 40 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 11 1367.00 XCSE

188

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:45:49 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 39 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:49 PM 1 1366.50 AQEU
GENMAB A/S 28-Mar-25 3:45:49 PM 20 1366.50 AQEU
GENMAB A/S 28-Mar-25 3:45:49 PM 10 1366.50 AQEU
GENMAB A/S 28-Mar-25 3:45:50 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 39 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 34 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 39 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:50 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:51 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:51 PM 35 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:51 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:45:51 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:46:07 PM 77 1366.00 XCSE
GENMAB A/S 28-Mar-25 3:46:07 PM 22 1366.00 TQEX
GENMAB A/S 28-Mar-25 3:46:08 PM 22 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:46:08 PM 20 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:46:51 PM 74 1366.50 XCSE
GENMAB A/S 28-Mar-25 3:46:51 PM 12 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:46:51 PM 25 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:46:51 PM 48 1366.50 TQEX
GENMAB A/S 28-Mar-25 3:46:57 PM 75 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:52:12 PM 8 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:52:12 PM 8 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:13 PM 9 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:22 PM 4 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:52:22 PM 4 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:22 PM 2 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:29 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:29 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:30 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:30 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:33 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:38 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 3:52:38 PM 9 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:39 PM 27 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:39 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:39 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:39 PM 6 1368.00 CEUX

189

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:52:48 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:52:53 PM 24 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:53:07 PM 31 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:53:27 PM 1 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:55:15 PM 13 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:15 PM 13 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:15 PM 1 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:15 PM 78 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:55:15 PM 42 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:15 PM 11 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 18 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 24 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 6 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 17 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 42 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 13 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:16 PM 82 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:55:28 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:55:28 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:55:28 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:55:28 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:55:28 PM 13 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:55:28 PM 14 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:55:28 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:55:57 PM 26 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:55:57 PM 36 1367.00 CEUX
GENMAB A/S 28-Mar-25 3:56:01 PM 67 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:56:01 PM 11 1366.50 CEUX
GENMAB A/S 28-Mar-25 3:56:01 PM 3 1366.50 TQEX
GENMAB A/S 28-Mar-25 3:57:31 PM 11 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:57:31 PM 25 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:57:31 PM 10 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:57:31 PM 20 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:58:16 PM 36 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:25 PM 11 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:26 PM 9 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:47 PM 77 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:58:47 PM 36 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:47 PM 66 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:48 PM 23 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:58:48 PM 78 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:25 PM 10 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:26 PM 16 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 80 1367.00 XCSE
GENMAB A/S 28-Mar-25 3:59:57 PM 5 1367.50 CEUX

190

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 3:59:57 PM 6 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 36 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 78 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 14 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:57 PM 30 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:58 PM 91 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:59:58 PM 2 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:59:58 PM 8 1367.50 XCSE
GENMAB A/S 28-Mar-25 3:59:58 PM 5 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:58 PM 25 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:58 PM 76 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:58 PM 6 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:59 PM 5 1367.50 CEUX
GENMAB A/S 28-Mar-25 3:59:59 PM 33 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:59 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:59 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 3:59:59 PM 36 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:00:00 PM 13 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:00:00 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:00:02 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:00:18 PM 2 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:00:21 PM 78 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:00:21 PM 32 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:00:31 PM 41 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 60 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:31 PM 6 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:00:31 PM 68 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:00:31 PM 76 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:00:31 PM 39 1367.00 AQEU
GENMAB A/S 28-Mar-25 4:00:32 PM 44 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:32 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:32 PM 35 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:32 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:45 PM 4 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:45 PM 30 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:45 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:45 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:45 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 11 1367.00 XCSE

191

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:00:46 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 30 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 3 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 33 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 38 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 47 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:46 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:47 PM 1 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:47 PM 14 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:00:58 PM 42 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:00:58 PM 59 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:01:00 PM 34 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:00 PM 43 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:00 PM 79 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:01:06 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:06 PM 41 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:06 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:06 PM 11 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:06 PM 11 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:07 PM 2 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 28 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 18 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 42 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:01:13 PM 76 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:01:13 PM 22 1365.50 AQEU
GENMAB A/S 28-Mar-25 4:01:15 PM 28 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:01:15 PM 59 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:01:25 PM 11 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:01:25 PM 12 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:02:23 PM 7 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:02:24 PM 8 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:02:26 PM 1 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:02:26 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:02:55 PM 37 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:02:55 PM 34 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:02:55 PM 40 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:02:55 PM 23 1365.50 AQEU

192

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:02:56 PM 39 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:02:56 PM 42 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:02:56 PM 24 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:03:05 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:03:28 PM 10 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:03:46 PM 34 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:03:46 PM 46 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:04:42 PM 11 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:04:52 PM 32 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:04:52 PM 41 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:04:52 PM 30 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:05:00 PM 11 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:05:11 PM 77 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:05:25 PM 12 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:05:43 PM 43 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:05:43 PM 37 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:05:43 PM 1 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:05:43 PM 38 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:05:43 PM 76 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:05:43 PM 25 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:06:37 PM 60 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:07:25 PM 1 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:07:25 PM 10 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:07:26 PM 1 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:07:30 PM 11 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:07:30 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:07:30 PM 36 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:07:30 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:07:30 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:07:30 PM 41 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:08:07 PM 14 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:07 PM 36 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:07 PM 78 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:07 PM 44 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:08:16 PM 23 1364.50 AQEU
GENMAB A/S 28-Mar-25 4:08:25 PM 36 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:25 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:25 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:26 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:26 PM 52 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:26 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:26 PM 23 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:27 PM 24 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:27 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:27 PM 12 1365.00 XCSE

193

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:08:27 PM 51 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:27 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:28 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:28 PM 27 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:30 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:30 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:33 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:08:38 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:38 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:38 PM 12 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:48 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:48 PM 7 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:48 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:48 PM 19 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:08:54 PM 42 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:08:54 PM 12 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:08:54 PM 42 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:08:54 PM 1 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:09:25 PM 3 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:09:25 PM 2 1364.50 AQEU
GENMAB A/S 28-Mar-25 4:09:29 PM 10 1364.50 AQEU
GENMAB A/S 28-Mar-25 4:10:02 PM 41 1364.50 TQEX
GENMAB A/S 28-Mar-25 4:10:07 PM 25 1364.50 AQEU
GENMAB A/S 28-Mar-25 4:10:48 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:10:48 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:10:54 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:03 PM 2 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:11:19 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:11:19 PM 6 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:11:19 PM 6 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:11:19 PM 9 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:11:19 PM 34 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:11:26 PM 10 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:11:32 PM 32 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:11:39 PM 42 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:39 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:39 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:39 PM 18 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:39 PM 15 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:40 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:40 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:40 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:40 PM 78 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:41 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:11:41 PM 13 1366.00 XCSE

194

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:11:57 PM 11 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:12:03 PM 2 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:12:26 PM 3 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 74 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:12:27 PM 74 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 2 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 2 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 2 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 2 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 15 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 3 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:27 PM 31 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:12:35 PM 41 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:37 PM 32 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 3 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 32 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 25 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 42 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 80 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 20 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 1 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 5 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 5 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 21 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 43 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 17 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 12 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 5 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 2 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 30 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 8 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 10 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 15 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 10 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 36 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 4 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 4 1363.50 CEUX

195

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:12:46 PM 3 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 10 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:12:46 PM 46 1364.50 TQEX
GENMAB A/S 28-Mar-25 4:12:47 PM 34 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:12:47 PM 2 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:13:27 PM 71 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:27 PM 6 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:27 PM 36 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:13:28 PM 41 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 21 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 8 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 42 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 11 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 10 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:28 PM 5 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:29 PM 11 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:29 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:29 PM 11 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:32 PM 13 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:32 PM 13 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:32 PM 42 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:13:33 PM 22 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:13:56 PM 44 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:00 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:00 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:00 PM 16 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:10 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:10 PM 42 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:10 PM 12 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:14:40 PM 11 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:14:40 PM 66 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:14:43 PM 12 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:43 PM 10 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:43 PM 77 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:43 PM 12 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:14:43 PM 35 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:14:43 PM 10 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:14:43 PM 29 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:14:52 PM 31 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 42 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 11 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 11 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 12 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 33 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 13 1364.00 XCSE

196

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:14:52 PM 11 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 27 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:52 PM 13 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 13 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 30 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 12 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 13 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 12 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:53 PM 42 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:54 PM 64 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:54 PM 15 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:55 PM 21 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:55 PM 42 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:55 PM 27 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:55 PM 13 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:55 PM 61 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:57 PM 11 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:14:57 PM 27 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:15:10 PM 80 1364.00 XCSE
GENMAB A/S 28-Mar-25 4:15:10 PM 79 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:15:10 PM 23 1364.00 TQEX
GENMAB A/S 28-Mar-25 4:15:59 PM 27 1364.00 AQEU
GENMAB A/S 28-Mar-25 4:16:13 PM 75 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:13 PM 4 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:13 PM 32 1364.00 CEUX
GENMAB A/S 28-Mar-25 4:16:13 PM 12 1364.00 AQEU
GENMAB A/S 28-Mar-25 4:16:14 PM 1 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:14 PM 3 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:14 PM 13 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:14 PM 75 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:15 PM 43 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:34 PM 25 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:16:51 PM 77 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:17:25 PM 12 1363.50 AQEU
GENMAB A/S 28-Mar-25 4:17:57 PM 4 1363.50 AQEU
GENMAB A/S 28-Mar-25 4:19:00 PM 28 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:19:00 PM 52 1363.50 XCSE
GENMAB A/S 28-Mar-25 4:19:00 PM 36 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:19:00 PM 7 1363.50 AQEU
GENMAB A/S 28-Mar-25 4:19:00 PM 2 1363.50 AQEU
GENMAB A/S 28-Mar-25 4:19:27 PM 2 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:19:27 PM 16 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:19:50 PM 11 1363.50 CEUX
GENMAB A/S 28-Mar-25 4:21:07 PM 49 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:21:07 PM 31 1364.50 XCSE

197

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:21:07 PM 27 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:21:07 PM 56 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:07 PM 77 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:07 PM 45 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:07 PM 35 1364.50 AQEU
GENMAB A/S 28-Mar-25 4:21:08 PM 14 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:30 PM 75 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:21:30 PM 8 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:30 PM 7 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:34 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:34 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:34 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:34 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:21:34 PM 17 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:43 PM 58 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:43 PM 36 1364.50 CEUX
GENMAB A/S 28-Mar-25 4:21:44 PM 4 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:21:44 PM 41 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:23:07 PM 46 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:23:32 PM 95 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:23:32 PM 2 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:23:32 PM 18 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:23:32 PM 14 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:23:32 PM 8 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:23:32 PM 10 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:23:57 PM 29 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:24:00 PM 30 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:24:00 PM 28 1365.00 TQEX
GENMAB A/S 28-Mar-25 4:24:00 PM 8 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:24:03 PM 8 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:24:37 PM 34 1364.50 XCSE
GENMAB A/S 28-Mar-25 4:24:37 PM 8 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:25:28 PM 8 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:26:28 PM 1 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:28 PM 59 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:28 PM 6 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:28 PM 11 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:32 PM 53 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:32 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:32 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:32 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:32 PM 36 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:32 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:32 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:33 PM 24 1365.00 CEUX

198

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:26:33 PM 21 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:33 PM 6 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:35 PM 12 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:35 PM 11 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:35 PM 13 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:35 PM 5 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:36 PM 42 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:26:36 PM 31 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:36 PM 21 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:41 PM 73 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:26:53 PM 45 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:26:53 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:26:53 PM 34 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:26:54 PM 41 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 28 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 17 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 5 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 48 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 8 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 31 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:49 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:50 PM 18 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:27:50 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:28:00 PM 3 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:28:27 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:28:27 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:28:42 PM 43 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:28:42 PM 28 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:28:42 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:28:42 PM 54 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:28:44 PM 11 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:29:03 PM 13 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:29:17 PM 35 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:17 PM 6 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:29:17 PM 36 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:29:17 PM 5 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:29:17 PM 25 1365.50 AQEU
GENMAB A/S 28-Mar-25 4:29:26 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 12 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 11 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 18 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 12 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 30 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 30 1365.50 XCSE

199

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:29:26 PM 11 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 12 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 30 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 21 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:26 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 36 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 17 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 26 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:26 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:29:27 PM 12 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:27 PM 9 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:29:27 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:30:17 PM 11 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:30:25 PM 2 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:30:43 PM 10 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:30:49 PM 3 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:31:04 PM 12 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:31:05 PM 42 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:31:31 PM 20 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:31:31 PM 30 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:31:37 PM 36 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:31:46 PM 62 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:31:55 PM 31 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:00 PM 11 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:00 PM 10 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:03 PM 15 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:03 PM 11 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:11 PM 58 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:12 PM 34 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:15 PM 28 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:16 PM 8 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:32:16 PM 17 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:16 PM 56 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:32:17 PM 2 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:32:28 PM 63 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:32:28 PM 10 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:32:28 PM 22 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:32:28 PM 15 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:32:28 PM 16 1366.00 AQEU

200

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:32:45 PM 51 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:46 PM 7 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:32:46 PM 64 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:32:46 PM 22 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:32:47 PM 23 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:32:48 PM 5 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:33:07 PM 48 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 10 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 25 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 2 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 53 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:26 PM 75 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:33:26 PM 24 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:33:27 PM 9 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:27 PM 42 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:27 PM 50 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:28 PM 73 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:31 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:31 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:31 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:31 PM 53 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:38 PM 5 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:39 PM 18 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:39 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:39 PM 53 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:39 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:40 PM 43 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:53 PM 53 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:53 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:53 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:33:54 PM 10 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:33:59 PM 16 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:34:00 PM 40 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:34:00 PM 22 1366.50 AQEU
GENMAB A/S 28-Mar-25 4:34:37 PM 5 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:34:37 PM 42 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:34:37 PM 36 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:34:37 PM 13 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:34:41 PM 30 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:34:41 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:34:41 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:34:41 PM 1 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:34:45 PM 7 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:45 PM 10 1367.00 XCSE

201

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:34:45 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:45 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:45 PM 30 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:45 PM 53 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:51 PM 12 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:34:51 PM 13 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 1 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 2 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 25 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 1 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 32 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:35:01 PM 28 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:01 PM 22 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:01 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:03 PM 2 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:03 PM 7 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:03 PM 15 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 2 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 1 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 10 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 2 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:03 PM 3 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:35:08 PM 79 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 5 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 53 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 15 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 7 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 10 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:08 PM 28 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 76 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:20 PM 21 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:35:20 PM 10 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:35:20 PM 45 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:35:20 PM 25 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:35:20 PM 3 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 7 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 4 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 4 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 2 1368.50 TQEX

202

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:35:20 PM 2 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:35:20 PM 22 1369.00 AQEU
GENMAB A/S 28-Mar-25 4:35:25 PM 10 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:25 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:25 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:26 PM 5 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:34 PM 25 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:35:34 PM 7 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:34 PM 14 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:35:37 PM 18 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:35:37 PM 12 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:35:37 PM 9 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:35:37 PM 36 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:35:37 PM 20 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:35:37 PM 6 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:35:37 PM 48 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:35:37 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:35:37 PM 5 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:35:37 PM 3 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:35:37 PM 3 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:35:37 PM 2 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:35:37 PM 6 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:35:37 PM 17 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:35:37 PM 5 1367.00 TQEX
GENMAB A/S 28-Mar-25 4:36:18 PM 65 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:18 PM 36 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:27 PM 15 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:36:30 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:30 PM 22 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:30 PM 1 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:30 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:30 PM 53 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:30 PM 12 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:36:31 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:31 PM 10 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:36:31 PM 53 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:31 PM 2 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:31 PM 24 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:36:31 PM 23 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:36:42 PM 7 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:36:57 PM 10 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:36:57 PM 11 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:36:57 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:36:57 PM 3 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:36:57 PM 8 1368.00 CEUX

203

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:36:59 PM 69 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:37:08 PM 6 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:37:08 PM 15 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:37:08 PM 6 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:37:08 PM 12 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:37:26 PM 7 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:37:26 PM 22 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:37:37 PM 10 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:37:37 PM 6 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:37:37 PM 6 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:37:37 PM 25 1367.00 AQEU
GENMAB A/S 28-Mar-25 4:37:46 PM 10 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:37:46 PM 63 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:38:34 PM 26 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:38:34 PM 30 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:38:34 PM 15 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:38:47 PM 65 1367.00 CEUX
GENMAB A/S 28-Mar-25 4:39:14 PM 22 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:39:14 PM 75 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:39:14 PM 8 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:39:16 PM 83 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:39:17 PM 12 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:39:37 PM 11 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:39:48 PM 52 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:40:32 PM 1 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:32 PM 1 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:32 PM 5 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:33 PM 90 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:40:33 PM 9 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:40:40 PM 53 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:40 PM 11 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:40 PM 3 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:45 PM 39 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:40:48 PM 53 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:48 PM 10 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:48 PM 12 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:48 PM 79 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:48 PM 12 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:40:48 PM 27 1367.50 TQEX
GENMAB A/S 28-Mar-25 4:41:00 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 32 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 42 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 2 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 25 1368.00 XCSE

204

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:41:00 PM 46 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 10 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:00 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:01 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:01 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:01 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:01 PM 93 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:03 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:03 PM 53 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:03 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:03 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:04 PM 12 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:04 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:04 PM 11 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:15 PM 5 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:41:17 PM 56 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:41:37 PM 53 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:37 PM 12 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:37 PM 11 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:39 PM 93 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:40 PM 53 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:40 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:41:40 PM 11 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:05 PM 12 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:05 PM 11 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:05 PM 53 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:06 PM 39 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:42:15 PM 46 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:42:18 PM 35 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:42:18 PM 19 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:42:18 PM 17 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:42:18 PM 42 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:42:18 PM 9 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:42:18 PM 42 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:42:18 PM 25 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:42:23 PM 13 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:23 PM 9 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:42:23 PM 12 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:43:02 PM 52 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:43:02 PM 11 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:43:02 PM 101 1369.00 CEUX
GENMAB A/S 28-Mar-25 4:43:18 PM 49 1369.00 CEUX
GENMAB A/S 28-Mar-25 4:43:27 PM 26 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:43:36 PM 28 1369.00 XCSE

205

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:43:36 PM 53 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:43:38 PM 37 1369.00 CEUX
GENMAB A/S 28-Mar-25 4:43:38 PM 8 1369.00 CEUX
GENMAB A/S 28-Mar-25 4:43:46 PM 40 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:43:46 PM 29 1369.00 AQEU
GENMAB A/S 28-Mar-25 4:43:49 PM 22 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:44:02 PM 28 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:02 PM 19 1369.00 XCSE
GENMAB A/S 28-Mar-25 4:44:08 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:08 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:08 PM 53 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:08 PM 50 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:08 PM 20 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:44:08 PM 22 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:44:13 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:23 PM 7 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:44:28 PM 10 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:44:28 PM 28 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:44:28 PM 10 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:44:28 PM 22 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:00 PM 12 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:08 PM 24 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:08 PM 42 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:28 PM 1 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:28 PM 4 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:28 PM 31 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:45:28 PM 2 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:46:15 PM 41 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:46:17 PM 33 1368.50 TQEX
GENMAB A/S 28-Mar-25 4:46:22 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:22 PM 5 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:22 PM 1 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:22 PM 5 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:22 PM 42 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:46:24 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:24 PM 1 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:24 PM 11 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:24 PM 44 1368.50 CEUX
GENMAB A/S 28-Mar-25 4:46:29 PM 30 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 53 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 13 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 8 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:29 PM 5 1368.50 XCSE

206

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:46:29 PM 12 1368.50 XCSE
GENMAB A/S 28-Mar-25 4:46:47 PM 21 1368.00 AQEU
GENMAB A/S 28-Mar-25 4:47:24 PM 1 1368.00 AQEU
GENMAB A/S 28-Mar-25 4:47:25 PM 30 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:47:25 PM 21 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:47:26 PM 11 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:47:37 PM 22 1368.00 AQEU
GENMAB A/S 28-Mar-25 4:47:55 PM 47 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:47:55 PM 34 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:47:55 PM 11 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:02 PM 47 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:48:02 PM 12 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:04 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:04 PM 42 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:04 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:05 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:48:05 PM 13 1368.00 XCSE
GENMAB A/S 28-Mar-25 4:48:05 PM 36 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:05 PM 2 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:05 PM 2 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:05 PM 11 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:07 PM 33 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:48:07 PM 37 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:07 PM 25 1367.50 TQEX
GENMAB A/S 28-Mar-25 4:48:07 PM 2 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:07 PM 11 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:07 PM 3 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:07 PM 6 1368.00 TQEX
GENMAB A/S 28-Mar-25 4:48:25 PM 33 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:48:36 PM 41 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:48:36 PM 8 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:48:52 PM 14 1367.00 AQEU
GENMAB A/S 28-Mar-25 4:48:52 PM 5 1367.00 AQEU
GENMAB A/S 28-Mar-25 4:48:55 PM 12 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:48:55 PM 34 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:49:19 PM 27 1368.00 AQEU
GENMAB A/S 28-Mar-25 4:49:26 PM 78 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:49:26 PM 17 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:49:26 PM 51 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:49:26 PM 5 1368.00 CEUX
GENMAB A/S 28-Mar-25 4:49:26 PM 18 1367.50 CEUX
GENMAB A/S 28-Mar-25 4:49:26 PM 23 1367.50 TQEX
GENMAB A/S 28-Mar-25 4:49:27 PM 13 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:49:27 PM 11 1367.50 XCSE
GENMAB A/S 28-Mar-25 4:49:45 PM 8 1367.00 AQEU

207

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:50:00 PM 11 1367.00 XCSE
GENMAB A/S 28-Mar-25 4:50:00 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:50:00 PM 8 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:50:14 PM 25 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:50:14 PM 5 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:50:19 PM 6 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:50:19 PM 4 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:50:24 PM 5 1366.50 TQEX
GENMAB A/S 28-Mar-25 4:50:47 PM 1 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:50:52 PM 1 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:50:57 PM 10 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:50:57 PM 5 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:50:57 PM 16 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:50:57 PM 1 1366.00 AQEU
GENMAB A/S 28-Mar-25 4:51:07 PM 42 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:07 PM 33 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:07 PM 24 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:07 PM 11 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:51:08 PM 2 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:08 PM 33 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:09 PM 101 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:51:09 PM 51 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:10 PM 12 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:10 PM 35 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:51:11 PM 13 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:51:11 PM 26 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:11 PM 30 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:51:12 PM 1 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:51:27 PM 45 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:51:27 PM 22 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:51:32 PM 12 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:51:32 PM 21 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:51:47 PM 70 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:52:07 PM 4 1365.00 XCSE
GENMAB A/S 28-Mar-25 4:52:10 PM 12 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:52:10 PM 35 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:52:10 PM 13 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:52:10 PM 10 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:52:10 PM 31 1366.00 CEUX
GENMAB A/S 28-Mar-25 4:52:34 PM 100 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:52:34 PM 11 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:52:34 PM 9 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:52:55 PM 5 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:52:57 PM 8 1365.00 CEUX
GENMAB A/S 28-Mar-25 4:52:57 PM 6 1365.50 CEUX

208

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:52:58 PM 53 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:52:58 PM 18 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:52:59 PM 5 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:52:59 PM 5 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:02 PM 11 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:19 PM 10 1365.00 AQEU
GENMAB A/S 28-Mar-25 4:53:26 PM 36 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:27 PM 13 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:53:27 PM 3 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:53:27 PM 85 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:53:27 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:27 PM 5 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:27 PM 6 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:27 PM 42 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:27 PM 2 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:27 PM 3 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:27 PM 3 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:27 PM 12 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:27 PM 2 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:28 PM 12 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:28 PM 62 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:28 PM 5 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:53:28 PM 22 1365.50 TQEX
GENMAB A/S 28-Mar-25 4:53:29 PM 6 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:53:38 PM 8 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:53:41 PM 42 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:41 PM 42 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:41 PM 6 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:41 PM 6 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:41 PM 5 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:51 PM 42 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:51 PM 6 1366.50 CEUX
GENMAB A/S 28-Mar-25 4:53:55 PM 101 1366.00 XCSE
GENMAB A/S 28-Mar-25 4:53:55 PM 33 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:53:55 PM 30 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:53:55 PM 7 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:53:55 PM 4 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:53:55 PM 5 1366.00 TQEX
GENMAB A/S 28-Mar-25 4:54:02 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:02 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:03 PM 26 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:03 PM 64 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:03 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:04 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:04 PM 12 1366.50 XCSE

209

Exhibit 99.1(a)

APPENDIX Share buy-back programme - Specification for March 26 – March 28, 2025

Graphic

GENMAB A/S 28-Mar-25 4:54:04 PM 30 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:04 PM 6 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:04 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:04 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:05 PM 55 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:07 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:07 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:07 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:14 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:14 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:14 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:15 PM 100 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:15 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:15 PM 13 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:15 PM 53 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:19 PM 100 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:33 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 1 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 12 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:40 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:41 PM 11 1366.50 XCSE
GENMAB A/S 28-Mar-25 4:54:45 PM 25 1365.50 CEUX
GENMAB A/S 28-Mar-25 4:54:51 PM 20 1365.50 AQEU
GENMAB A/S 28-Mar-25 4:54:56 PM 23 1365.50 XCSE
GENMAB A/S 28-Mar-25 4:54:58 PM 21 1365.50 XCSE

210