REG — Great Portland Ests. — Holding(s) in Company

For best results when printing this announcement, please click on link below: RNS Number: 3789V Great Portland Estates plc 18 September 2026 Great Portland Estates plc Great Portland Estates plc announces that on 17 September 2026, it received the Notification of Major Holdings as set out below. Darren Lennark General Counsel & Company Secretary Great Portland Estates plc 020 7647 3000 18 September 2026 TR-1: Standard form for notification of major holdings 1. Issuer Details ISIN GB00BF5H9P87 Issuer Name GREAT PORTLAND ESTATES P L C 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 16-Sep-2026 6.

Date on which Issuer notified 17-Sep-2026 7. 980000 8. Notified details of the resulting situation on the date on which the threshold was crossed or reached 8A. 790000% 8B1.

480000% 8B2. 450000% 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 Total of both if it equals or is higher than the notifiable threshold 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. P. BlackRock, Inc. (Chain 1) BlackRock (Singapore) Holdco Pte.

Ltd. BlackRock, Inc. (Chain 1) BlackRock HK Holdco Limited BlackRock, Inc. l.

BlackRock, Inc. (Chain 1) BlackRock Japan Holdings GK BlackRock, Inc. , 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. 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. 110000% 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. 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 Holdco 4, LLC BlackRock, Inc. (Chain 5) BlackRock Holdco 6, LLC BlackRock, Inc. (Chain 5) BlackRock Delaware Holdings Inc. BlackRock, Inc.

(Chain 5) BlackRock Institutional Trust Company, National Association 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 Fund Advisors 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 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 8) BlackRock International Holdings, Inc.

BlackRock, Inc. (Chain 8) BlackRock Canada Holdings ULC BlackRock, Inc. (Chain 8) BlackRock Asset Management Canada Limited 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 Capital Holdings, Inc. BlackRock, Inc.

(Chain 9) BlackRock Advisors, LLC 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. 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 Advisors (UK) Limited 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 If date does not apply, explain below 11. Additional Information BlackRock Regulatory Threshold Reporting Team Jana Blumenstein 020 7743 3650 12.

Date of Completion 17(th) September 2026 13. K. This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom.

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