Holding(s) in Company

TR-1: Standard form for notification of major holdings

1. Issuer Details
ISIN
GB00BLDRH360
Issuer Name
OSB GROUP PLC
UK or Non-UK Issuer
UK
2. Reason for Notification
An acquisition or disposal of voting rights; An acquisition or disposal of financial instruments
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
15-Aug-2024
6. Date on which Issuer notified
16-Aug-2024
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	4.680000	0.320000	5.000000	19357170
Position of previous notification (if applicable)	Below 5%	Below 5%	Below 5%

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)
GB00BLDRH360		18114991		4.680000
Sub Total 8.A	18114991		4.680000%

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
Securities Lending			188732	0.050000
Sub Total 8.B1			188732	0.050000%

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	1053447	0.270000
Sub Total 8.B2				1053447	0.270000%

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 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 Holdco 3, LLC
BlackRock, Inc. (Chain 1)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 1)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 1)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 1)	BlackRock Group Limited
BlackRock, Inc. (Chain 1)	BlackRock Finance Europe Limited
BlackRock, Inc. (Chain 1)	BlackRock Investment Management (UK) Limited
BlackRock, Inc. (Chain 2)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 2)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 2)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 2)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 2)	BlackRock Australia Holdco Pty. Ltd.
BlackRock, Inc. (Chain 2)	BlackRock Investment Management (Australia) Limited
BlackRock, Inc. (Chain 3)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 3)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 3)	BlackRock Holdco 4, LLC
BlackRock, Inc. (Chain 3)	BlackRock Holdco 6, LLC
BlackRock, Inc. (Chain 3)	BlackRock Delaware Holdings Inc.
BlackRock, Inc. (Chain 3)	BlackRock Institutional Trust Company, National Association
BlackRock, Inc. (Chain 4)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 4)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 4)	BlackRock Holdco 4, LLC
BlackRock, Inc. (Chain 4)	BlackRock Holdco 6, LLC
BlackRock, Inc. (Chain 4)	BlackRock Delaware Holdings Inc.
BlackRock, Inc. (Chain 4)	BlackRock Fund Advisors
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)	BlackRock Canada Holdings ULC
BlackRock, Inc. (Chain 5)	BlackRock Asset Management Canada Limited
BlackRock, Inc. (Chain 6)	BlackRock Holdco 2, Inc.
BlackRock, Inc. (Chain 6)	BlackRock Financial Management, Inc.
BlackRock, Inc. (Chain 6)	BlackRock International Holdings, Inc.
BlackRock, Inc. (Chain 6)	BR Jersey International Holdings L.P.
BlackRock, Inc. (Chain 6)	BlackRock Holdco 3, LLC
BlackRock, Inc. (Chain 6)	BlackRock Cayman 1 LP
BlackRock, Inc. (Chain 6)	BlackRock Cayman West Bay Finco Limited
BlackRock, Inc. (Chain 6)	BlackRock Cayman West Bay IV Limited
BlackRock, Inc. (Chain 6)	BlackRock Group Limited
BlackRock, Inc. (Chain 6)	BlackRock Finance Europe Limited
BlackRock, Inc. (Chain 6)	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

11. Additional Information
BlackRock Regulatory Threshold Reporting Team

Jana Blumenstein

020 7743 3650
12. Date of Completion
16^th August 2024
13. Place Of Completion
12 Throgmorton Avenue, London, EC2N 2DL, U.K.