Osb Group PlcLSE: OSB

Holding(s) in Company

· Issued by Osb Group Plc

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
3. Details of person subject to the notification obligation
Name
Dimensional Fund Advisors LP
City of registered office (if applicable)
Austin
Country of registered office (if applicable)
USA
4. Details of the shareholder

Name

City of registered office

Country of registered office

Funds and accounts managed by Dimensional Fund Advisors LP and/or its subsidiary undertakings

5. Date on which the threshold was crossed or reached
22-Jan-2026
6. Date on which Issuer notified
26-Jan-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

5.003594

0.000000

5.003594

17769925

Position of previous notification (if applicable)

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

17769925

5.003594

Sub Total 8.A

17769925

5.003594%

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

Sub Total 8.B1

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

Sub Total 8.B2

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

Dimensional Holdings Inc.

i) Dimensional Fund Advisors Ltd., (ii) DFA Australia Limited (iii) Dimensional Ireland Limited (iv) Dimensional Fund Advisors Canada ULC (v) Dimensional Fund Advisors Pte. Ltd. and (vi) Dimensional Fund Advisors LP

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
The ordinary shares are held in segregated accounts and funds (together, the “Accounts”) managed on a discretionary basis by Dimensional Fund Advisors LP ("Dimensional") and its subsidiary undertakings i) Dimensional Fund Advisors Ltd., (ii) DFA Australia Limited (iii) Dimensional Ireland Limited (iv) Dimensional Fund Advisors Canada ULC (v) Dimensional Fund Advisors Pte. Ltd. and (vi) Dimensional Fund Advisors LP.

As at 22 January 2026, Dimensional also had investment management discretion over an additional 48,869 shares where the voting rights are not controlled by Dimensional or its subsidiary undertakings.

Dimensional is controlled by its general partner, Dimensional Holdings Inc.

Dimensional, on behalf of itself and its subsidiary undertakings, expressly disclaims beneficial ownership of the shares held in the Accounts.
12. Date of Completion
26-Jan-2026
13. Place Of Completion
Paris