6-K

MATERIALISE NV (MTLS)

6-K 2025-12-02 For: 2025-12-02
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

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of December 2025

Commission File Number: 001-36515

Materialise NV

Technologielaan 15

3001 Leuven

Belgium

(Address of principal executive office)

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

Form 20-F  x           Form 40-F  ¨

Attached as Exhibit 99.1 hereto is a copy of a press release regarding the receipt by Materialise NV of a transparency notification.

EXHIBIT INDEX

Exhibit Description
99.1 Press Release dated December 2, 2025

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.

MATERIALISE NV
By: /s/ Brigitte de Vet-Veithen
Name: Brigitte de Vet-Veithen
De Vet Management BV
Title: Chief Executive Officer

Date: December 2, 2025

Exhibit 99.1

Publicationof transparency notification

(article14, first paragraph, of the Law of 2 May 2007 on the disclosure of large shareholdings)

Regulated information[1]

Leuven(Belgium) – December, 2 2025, 22:30 CET – Materialise NV (Euronext & Nasdaq: MTLS), a global leader in 3D-printed medical devices and software, and a pioneer in additive manufacturing software and services, today announces, in application of article 14, first paragraph, of the Law of May 2, 2007 on the disclosure of large shareholdings in issuers whose shares are admitted to trading on a regulated market (the Transparency Law), that on November 28, 2025 it received a transparency notification from Wilfried Vancraen, Hilde Ingelaere and the IDEM partnership.

The notification contains the following information:

· Date<br> of the notification: November 28, 2025
· Reason<br> for the notification: holding of voting securities upon first admission to trading
--- ---
· Notification<br> by: a parent undertaking or a controlling person
--- ---
· Persons<br> subject to the notification requirement:
--- ---
Name Address (for legal entities)
--- ---
Wilfried<br> Vancraen
Hilde<br> Ingelaere
Wilfried<br> Vancraen & Hilde Ingelaere
IDEM J.<br> Van der Vorstlaan 19, 3040 Huldenberg, Belgium
· Date<br> on which the threshold is crossed: November 20, 2025
--- ---
· Threshold<br> that is crossed: 70%
--- ---
· Denominator:<br> 90,712,021
--- ---
· Notified<br> details:
--- ---
Voting rights Previous<br><br> notification After the transaction
--- --- --- --- --- --- --- --- --- ---
# of voting rights # of voting rights % of voting rights
Holders of voting rights Linked to securities Not linked to the securities Linked to securities Not linked to the securities
Wilfried Vancraen 248,225 0.27 %
Hilde Ingelaere 248,225 0.27 %
Wilfried Vancraen & Hilde Ingelaere 50,000 0.06 %
IDEM 64,768,818 71.40 %
Total 65,315,268 0 72.00 % 0.00 %

[1] The enclosed information constitutes regulated information as defined in the Royal Decree of 14 November 2007 regarding the duties of issuers of financial instruments which have been admitted for trading on a regulated market.

1

· Chain<br> of control: IDEM, civil partnership, is controlled by Mr Wilfried Vancraen and Ms Hilde Ingelaere<br> in accordance with articles 1:14-1:18 of the Code of companies and associations (CCA).

The transparency notice is available at https://investors.materialise.com/.

About Materialise

Materialise incorporates more than three decades of 3D printing experience into a range of software solutions and 3D printing services that empower sustainable 3D printing applications. Our open, secure, and flexible end-to-end solutions enable industrial manufacturing and mass personalization in various industries — including healthcare, automotive, aerospace, eyewear, art and design, wearables, and consumer goods. Headquartered in Belgium and with branches worldwide, Materialise combines the largest group of software developers in the industry with one of the world's largest and most complete 3D printing facilities.

For more information,please contact:

Felix Theus

T: +32 16 39 66 11

E:felix.theus@materialise.be

Lina Galvis

T: +32 16 39 66 11

E:lina.galvis@materialise.be

2