NGG 6-K

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

Date: 30 June 2025

Commission File Number: 001-14958

NATIONAL GRID plc

(Translation of registrant’s name into English)

England and Wales

(Jurisdiction of Incorporation)

1-3 Strand, London, WC2N 5EH, United Kingdom

(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      ☐  Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3- 2(b) under the Securities Exchange Act of 1934.  ☐  Yes    ☒  No

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): n/a

EXHIBIT INDEX

Exhibit 99.1

2 June 2025

National Grid plc ('National Grid' or 'Company')

Voting Rights update

National Grid's registered capital as of 31 May 2025 consisted of 5,132,617,708 ordinary shares, of which, 230,984,649 were held as treasury shares; leaving a balance of 4,901,633,059 with voting rights.

The figure of 4,901,633,059 may be used by shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, National Grid under the FCA's Disclosure Guidance and Transparency Rules.

Julian Baddeley

Group Company Secretary

Exhibit 99.2

10 June 2025

National Grid plc ('National Grid' or 'Company')

Notification of Transactions of Persons Discharging Managerial Responsibilities ('PDMRs')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR'). In accordance with MAR, the relevant Financial Conduct Authority ('FCA') notifications are set out below.

Exhibit 99.3

16 June 2025

National Grid plc ('National Grid' or 'Company')

Notification of Transactions of Persons Discharging Managerial Responsibilities ('PDMRs')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR') and relates to the following Executive Directors and PDMRs being granted awards under the Company's Annual Performance Plan ('APP') on 13 June 2025, which relates to a percentage of the award for 2024/25 being paid in shares, and which (after tax on the gross award) must be retained until the shareholding requirement is met, and in any event for two years after receipt. This award is subject to clawback and malus provisions.

For further details of the APP, please see the Company's 2024/25 Annual Report and Accounts.

In accordance with MAR the relevant Financial Conduct Authority ('FCA') notifications are set out below.

Exhibit 99.4

24 June 2025

National Grid plc ('National Grid' or 'Company')

Notification of Transactions of Persons Discharging Managerial Responsibilities ('PDMRs')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR') and relates to the following PDMRs being granted awards under the Company's Long Term Performance Plan ('LTPP') on 23 June 2025.

Each of the LTPP Awards will vest on or after 30 June 2028 and are conditional on continued employment and on the satisfaction of the performance conditions approved by the Remuneration Committee.

In addition, as disclosed in the Company's 2024/25 Annual Report and Accounts, Executive Directors are required to retain the after-tax value of any shares under the LTPP award until the shareholding requirement is met, and in any event for two years after receipt. The LTPP award is subject to clawback and malus provisions. For further details of the LTPP, please see the Company's 2024/25 Annual Report and Accounts.

In accordance with MAR, the relevant Financial Conduct Authority notifications are set out below.

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.

Date: 30 June 2025