BlackRock discloses 8.17% voting stake in National Grid plc

Rhea-AI Filing Summary

National Grid plc reports that BlackRock, Inc. has notified a major holding in its ordinary shares under the UK Disclosure and Transparency Rules. BlackRock now holds a total of 8.17% of National Grid’s voting rights, corresponding to 406,584,816 voting rights in the company. This compares with a previous notified total of 8.12%.

The position includes 7.32% of voting rights attached to shares, representing 363,408,544 voting rights, and 0.85% through financial instruments, including American Depositary Receipts, securities lending and cash-settled CFDs. The notice confirms compliance with UK transparency requirements and lists the BlackRock group entities through which the holding is managed.

Form 6-K: How Foreign Companies Report to the SEC →

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: 25 November 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 No.	Description
99.1	Exhibit 99.1 Announcement sent to the London Stock Exchange on 25 November 2025 — Holding(s) in Company

Exhibit 99.1

25 November 2025

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

Notification of Major Interest in National Grid Ordinary Shares

National Grid has received a notification on Form TR-1 from BlackRock, Inc. that its total interest in National Grid voting ordinary shares is as shown below.

TR-1: Standard form for notification of major holdings

1. Issuer Details

ISIN

GB00BDR05C01

Issuer Name

NATIONAL GRID PLC

UK or Non-UK Issuer

UK

2. Reason for Notification

An acquisition or disposal of voting rights

3. Details of person subject to the notification obligation

Name

BlackRock, Inc.

City of registered office (if applicable)

Wilmington

Country of registered office (if applicable)

USA

4. Details of the shareholder

Full name of shareholder(s) if different from the person(s) subject to the notification obligation, above

City of registered office (if applicable)

Country of registered office (if applicable)

5. Date on which the threshold was crossed or reached

24-Nov-2025

6. Date on which Issuer notified

25-Nov-2025

7. Total positions of person(s) subject to the notification obligation

	% of voting rights attached to shares (total of 8.A)	% of voting rights through financial instruments (total of 8.B 1 + 8.B 2)	Total of both in % (8.A + 8.B)	Total number of voting rights held in issuer
Resulting situation on the date on which threshold was crossed or reached	7.320000	0.850000	8.170000	406584816
Position of previous notification (if applicable)	4.870000	3.250000	8.120000

8. Notified details of the resulting situation on the date on which the threshold was crossed or reached

8A. Voting rights attached to shares

Class/Type of shares ISIN code(if possible)	Number of direct voting rights (DTR5.1)	Number of indirect voting rights (DTR5.2.1)	% of direct voting rights (DTR5.1)	% of indirect voting rights (DTR5.2.1)
GB00BDR05C01		363408544		7.320000
Sub Total 8.A	363408544		7.320000%

8B1. Financial Instruments according to (DTR5.3.1R.(1) (a))

Type of financial instrument	Expiration date	Exercise/conversion period	Number of voting rights that may be acquired if the instrument is exercised/converted	% of voting rights
American Depository Receipt			5172395	0.100000
Securities Lending			36210021	0.720000
Sub Total 8.B1			41382416	0.820000%

8B2. Financial Instruments with similar economic effect according to (DTR5.3.1R.(1) (b))

Type of financial instrument	Expiration date	Exercise/conversion period	Physical or cash settlement	Number of voting rights	% of voting rights
CFD			Cash	1793856	0.030000
Sub Total 8.B2				1793856	0.030000%

9. Information in relation to the person subject to the notification obligation

2. Full chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held starting with the ultimate controlling natural person or legal entities (please add additional rows as necessary)

Ultimate controlling person	Name of controlled undertaking	% of voting rights if it equals or is higher than the notifiable threshold	% of voting rights through financial instruments if it equals or is higher than the notifiable threshold	Total of both if it equals or is higher than the notifiable threshold
BlackRock, Inc. (Chain 1)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 1)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 1)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 1)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 1)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 1)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 1)	BlackRock (Singapore) Holdco Pte. Ltd.
BlackRock, Inc. (Chain 1)	BlackRock HK Holdco Limited
BlackRock, Inc. (Chain 1)	BlackRock Lux Finco S.a.r.l.
BlackRock, Inc. (Chain 1)	BlackRock Japan Holdings GK
BlackRock, Inc. (Chain 1)	BlackRock Japan Co., Ltd.
BlackRock, Inc. (Chain 2)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 2)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 2)	Trident Merger, LLC
BlackRock, Inc. (Chain 2)	BlackRock Investment Management, LLC
BlackRock, Inc. (Chain 3)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 3)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 3)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 3)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 3)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 3)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 3)	BlackRock Holdco 3, LLC
BlackRock, Inc. (Chain 3)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 3)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 3)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 3)	BlackRock Group Limited
BlackRock, Inc. (Chain 3)	BlackRock Finance Europe Limited
BlackRock, Inc. (Chain 3)	BlackRock Investment Management (UK) Limited
BlackRock, Inc. (Chain 4)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 4)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 4)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 4)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 4)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 4)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 4)	BlackRock Australia Holdco Pty. Ltd.
BlackRock, Inc. (Chain 4)	BlackRock Investment Management (Australia) Limited
BlackRock, Inc. (Chain 5)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 5)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 5)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 5)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 5)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 5)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 5)	BlackRock Holdco 3, LLC
BlackRock, Inc. (Chain 5)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 5)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 5)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 5)	BlackRock Group Limited
BlackRock, Inc. (Chain 5)	BlackRock International Limited
BlackRock, Inc. (Chain 6)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 6)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 6)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 6)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 6)	BlackRock Holdco 4, LLC
BlackRock, Inc. (Chain 6)	BlackRock Holdco 6, LLC
BlackRock, Inc. (Chain 6)	BlackRock Delaware Holdings Inc.
BlackRock, Inc. (Chain 6)	BlackRock Institutional Trust Company, National Association
BlackRock, Inc. (Chain 7)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 7)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 7)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 7)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 7)	BlackRock Holdco 4, LLC
BlackRock, Inc. (Chain 7)	BlackRock Holdco 6, LLC
BlackRock, Inc. (Chain 7)	BlackRock Delaware Holdings Inc.
BlackRock, Inc. (Chain 7)	BlackRock Fund Advisors
BlackRock, Inc. (Chain 8)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 8)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 8)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 8)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 9)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 9)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 9)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 9)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 9)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 9)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 9)	BlackRock (Singapore) Holdco Pte. Ltd.
BlackRock, Inc. (Chain 9)	BlackRock HK Holdco Limited
BlackRock, Inc. (Chain 9)	BlackRock Asset Management North Asia Limited
BlackRock, Inc. (Chain 10)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 10)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 10)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 10)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 10)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 10)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 10)	BlackRock Holdco 3, LLC
BlackRock, Inc. (Chain 10)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 10)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 10)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 10)	BlackRock Group Limited
BlackRock, Inc. (Chain 10)	BlackRock Finance Europe Limited
BlackRock, Inc. (Chain 10)	BlackRock (Netherlands) B.V.
BlackRock, Inc. (Chain 10)	BlackRock Asset Management Deutschland AG
BlackRock, Inc. (Chain 11)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 11)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 11)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 11)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 11)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 11)	BlackRock Canada Holdings ULC
BlackRock, Inc. (Chain 11)	BlackRock Asset Management Canada Limited
BlackRock, Inc. (Chain 12)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 12)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 12)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 12)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 12)	BlackRock Capital Holdings, Inc.
BlackRock, Inc. (Chain 12)	BlackRock Advisors, LLC
BlackRock, Inc. (Chain 13)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 13)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 13)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 13)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 13)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 13)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 13)	BlackRock Holdco 3, LLC
BlackRock, Inc. (Chain 13)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 13)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 13)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 13)	BlackRock Group Limited
BlackRock, Inc. (Chain 13)	BlackRock Finance Europe Limited
BlackRock, Inc. (Chain 13)	BlackRock Advisors (UK) Limited
BlackRock, Inc. (Chain 14)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 14)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 14)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 14)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 14)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 14)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 14)	BlackRock (Singapore) Holdco Pte. Ltd.
BlackRock, Inc. (Chain 14)	BlackRock (Singapore) Limited
BlackRock, Inc. (Chain 15)	BlackRock Saturn Subco, LLC
BlackRock, Inc. (Chain 15)	BlackRock Finance, Inc.
BlackRock, Inc. (Chain 15)	Trident Merger, LLC
BlackRock, Inc. (Chain 15)	BlackRock Investment Management, LLC
BlackRock, Inc. (Chain 15)	Amethyst Intermediate, LLC
BlackRock, Inc. (Chain 15)	Aperio Holdings, LLC
BlackRock, Inc. (Chain 15)	Aperio Group, LLC

10. In case of proxy voting

Name of the proxy holder

The number and % of voting rights held

The date until which the voting rights will be held

11. Additional Information

BlackRock Regulatory Threshold Reporting Team

Jana Blumenstein

020 7743 3650

12. Date of Completion

25th November 2025

13. Place Of Completion

12 Throgmorton Avenue, London, EC2N 2DL, U.K.

This notice is in compliance with National Grid's obligations under the Disclosure and Transparency Rules.

Julian Baddeley 

Group Company Secretary

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.

	NATIONAL GRID plc
	By:	Beth Melges
		Beth Melges Head of Plc Governance

Date: 25 November 2025

FAQ

What did National Grid plc (NGG) announce in this Form 6-K?

National Grid plc announced that it received a Form TR-1 notification from BlackRock, Inc. disclosing an updated major holding in National Grid’s ordinary shares and voting rights.

How large is BlackRock’s current voting interest in National Grid plc (NGG)?

BlackRock’s total interest amounts to 8.17% of National Grid’s voting rights, representing 406,584,816 voting rights in the company.

How is BlackRock’s 8.17% holding in National Grid (NGG) structured?

BlackRock holds 7.32% of voting rights attached to shares (363,408,544 voting rights) and 0.85% through financial instruments, including American Depositary Receipts, securities lending and CFDs.

How did BlackRock’s ownership in National Grid plc change from the previous notification?

The total voting interest increased from 8.12% to 8.17%. The prior position was 4.87% via shares and 3.25% via financial instruments, compared with the new mix of 7.32% via shares and 0.85% via financial instruments.

What types of financial instruments does BlackRock use for its National Grid exposure?

BlackRock’s financial instrument exposure includes American Depositary Receipts (5,172,395 voting rights, 0.10%), securities lending (36,210,021 voting rights, 0.72%), and CFDs (1,793,856 voting rights, 0.03%).

Why is this National Grid (NGG) holding announcement being disclosed?

The notice is disclosed to comply with UK Disclosure and Transparency Rules, which require National Grid to announce when a shareholder such as BlackRock crosses specified major shareholding thresholds.