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: 29 May 2026

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 01 May 2026 — Total Voting Rights
99.2	Exhibit 99.2 Announcement sent to the London Stock Exchange on 11 May 2026 — Director/PDMR Shareholding
99.3	Exhibit 99.3 Announcement sent to the London Stock Exchange on 19 May 2026 — Director/PDMR Shareholding
99.4	Exhibit 99.4 Announcement sent to the London Stock Exchange on 20 May 2026 — Director/PDMR Shareholding
99.5	Exhibit 99.5 Announcement sent to the London Stock Exchange on 22 May 2026 — Director/PDMR Shareholding
99.6	Exhibit 99.6 Announcement sent to the London Stock Exchange on 26 May 2026 — Holding(s) in Company

Exhibit 99.1

1 May 2026

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

Voting Rights update

National Grid's registered capital as of 30 April 2026 consisted of 5,198,968,690 ordinary shares, of which, 223,421,690 were held as treasury shares; leaving a balance of 4,975,547,000 with voting rights.

The figure of 4,975,547,000 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

11 May 2026

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

Notification of Transactions of Person 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') notification is set out below.

1	Details of the person discharging managerial responsibilities / person closely associated
a)	Name	Andy Agg
2	Reason for the notification
a)	Position/status	Chief Financial Officer
b)	Initial notification /Amendment	Initial notification
3	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	National Grid plc
b)	LEI	8R95QZMKZLJX5Q2XR704
4	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted
a)	Description of the financial instrument, type of instrument Identification code	Ordinary shares of 12 204/473p each GB00BDR05C01
b)	Nature of the transaction	Monthly purchase of securities ("partnership shares") under the Share Incentive Plan
c)	Price(s) and volume(s)	Price(s)	Volume(s)
		GBP 12.8356	12
d)	Aggregated information - Aggregated volume - Price
e)	Date of the transaction	2026.05.07
f)	Place of the transaction	London Stock Exchange (XLON)

Exhibit 99.3

19 May 2026

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

Notification of Transaction of Person Discharging Managerial Responsibilities ('PDMR')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR') and relates to the purchase of American Depositary Shares by Paula Rosput Reynolds. On 18 May 2026, the Company received notification of the following transaction as detailed below.

In accordance with MAR the relevant Financial Conduct Authority notification is set out below.

1	Details of the person discharging managerial responsibilities / person closely associated
a)	Name	Paula Rosput Reynolds
2	Reason for the notification
a)	Position/status	Chair
b)	Initial notification /Amendment	Initial notification
3	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	National Grid plc
b)	LEI	8R95QZMKZLJX5Q2XR704
4	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted
a)	Description of the financial instrument, type of instrument Identification code	American Depository Shares  US 6362744095
b)	Nature of the transaction	Purchase of American Depository Shares.
c)	Price(s) and volume(s)	Price(s)	Volume(s)
		USD 82.5350	1000
d)	Aggregated information - Aggregated volume - Price
e)	Date of the transaction	2026.05.18
f)	Place of the transaction	New York Stock Exchange (NYSE)

Exhibit 99.4

20 May 2026

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

Notification of Transaction of Person Discharging Managerial Responsibilities ('PDMR')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR') and relates to the purchase of American Depositary Shares by Earl Shipp. On 19 May 2026, the Company received notification of the following transaction as detailed below.

In accordance with MAR the relevant Financial Conduct Authority notification is set out below.

1	Details of the person discharging managerial responsibilities / person closely associated
a)	Name	Earl Shipp
2	Reason for the notification
a)	Position/status	Non-executive Director
b)	Initial notification /Amendment	Initial notification
3	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	National Grid plc
b)	LEI	8R95QZMKZLJX5Q2XR704
4	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted
a)	Description of the financial instrument, type of instrument Identification code	American Depository Shares  US 6362744095
b)	Nature of the transaction	Purchase of American Depository Shares.
c)	Price(s) and volume(s)	Price(s)	Volume(s)
		USD 84.435	118.4342
d)	Aggregated information - Aggregated volume - Price
e)	Date of the transaction	2026.05.19
f)	Place of the transaction	New York Stock Exchange (NYSE)

Exhibit 99.5

22 May 2026

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

Notification of Transaction of Person Discharging Managerial

Responsibilities ('PDMRs')

This announcement is made in accordance with Article 19 of the Market Abuse Regulation ('MAR') and relates to the purchase of Ordinary Shares by Jacqui Ferguson. On 22 May 2026, the Company received notification of the following transaction as detailed below.

In accordance with MAR, the relevant Financial Conduct Authority notification is set out below.

1	Details of the person discharging managerial responsibilities / person closely associated
a)	Name	Jacqui Ferguson
2	Reason for the notification
a)	Position/status	Non-executive Director
b)	Initial notification /Amendment	Initial notification
3	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	National Grid plc
b)	LEI	8R95QZMKZLJX5Q2XR704
4	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted
a)	Description of the financial instrument, type of instrument Identification code	Ordinary shares of 12 204/473p each GB00BDR05C01
b)	Nature of the transaction	Purchase of ordinary shares.
c)	Price(s) and volume(s)	Price(s)	Volume(s)
		GBP 12.8145	1,936
d)	Aggregated information - Aggregated volume - Price
e)	Date of the transaction	2026.05.22
f)	Place of the transaction	London Stock Exchange (XLON)

Exhibit 99.6

26 May 2026

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

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

22-May-2026

6. Date on which Issuer notified

25-May-2026

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	4.940000	3.480000	8.420000	419793494
Position of previous notification (if applicable)	7.320000	0.850000	8.170000

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		245824545		4.940000
Sub Total 8.A	245824545		4.940000%

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			5981459	0.120000
Securities Lending			165147748	3.310000
Sub Total 8.B1			171129207	3.430000%

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	2839742	0.050000
Sub Total 8.B2				2839742	0.050000%

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 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 (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 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 May 2026

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: 29 May 2026

NATIONAL GRID PLC 6-K