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

3.   Details of person subject to the notification obligation

Name

Lorentzweiler Adjacent Partners S.C.Sp.

City of registered office (if applicable)

Howald

Country of registered office (if applicable)

Luxembourg

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

01-Sep-2026

6.   Date on which Issuer notified

03-Sep-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	3.096900	0.000000	3.096900	10509837
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	10509837	0	3.096900	0.000000
Sub Total 8.A	10509837		3.096900%

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
Alan Waxman		3.096900		3.096900%
Alan Waxman	Sixth Street Partners Management Company, L.P.	3.096900		3.096900%
Alan Waxman	TAO Finance 3, LLC	1.858100		1.858100%
Alan Waxman	Beacon Finance 3, LLC	0.619400		0.619400%
Alan Waxman	Sixth Street Madrone Strategic Holdings I, L.P	0.619400		0.619400%
Alan Waxman	Lorentzweiler Adjacent Partners, S.C.Sp (acting through its general partner, Lorentzweiler Adjacent Investments, S.à r.l.)	3.096900		3.096900%

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

Lorentzweiler Adjacent Partners S.C.Sp is owned (i) 60% by TAO
Finance 3, LLC, which is controlled by its manager, Sixth Street TAO GenPar, L.P., (ii) 20% by Beacon Finance 3, LLC, which is controlled by its general partner, Sixth Street ABF Beacon GenPar I, L.P., and (iii) 20% by Sixth Street Madrone Strategic Holdings I, L.P. which is controlled by its general partner, Sixth Street Madrone Strategic Holdings GenPar, L.P.. Its general partner, Lorentzweiler Adjacent Investments, S.à r.l., is owned equally by such persons.

Each of foregoing entities are ultimately indirectly controlled by Sixth
Street Partners Management Company, L.P. Sixth Street Partners Management Company, L.P. is managed by its general partner, whose managing member is Alan Waxman.

Mr. Waxman disclaims beneficial ownership of the shares that are the subject of this notification except to the extent of his pecuniary interest therein.

12.     Date of Completion

03-Sep-2026

13.     Place Of Completion

Luxembourg