TR-1: Standard form for notification of major holdings

1. Issuer Details

ISIN

GB00BMCLYF79

Issuer Name

4BASEBIO 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

Wilhelm K. T. Zours

City of registered office (if applicable)

Heidelberg

Country of registered office (if applicable)

Germany

4. Details of the shareholder

Name City of registered office Country of registered office DELPHI Unternehmensberatung Heidelberg Germany Aktiengesellschaft

5. Date on which the threshold was crossed or reached

06-Feb-2023

6. Date on which Issuer notified

08-Feb-2023

7. Total positions of person(s) subject to the notification obligation

. % of voting % of voting Total of both in Total number of rights attached rights through % (8.A + 8.B) voting rights to shares financial held in issuer (total of 8.A) instruments (total of 8.B 1 + 8.B 2) Resulting 22.006560 0.000000 22.006560 2710652 situation on the date on which threshold was crossed or reached Position of 21.294839 0.081185 21.376024 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 Number of direct Number of % of direct % of indirect shares ISIN code voting rights indirect voting voting rights voting rights (if possible) (DTR5.1) rights (DTR5.2.1) (DTR5.1) (DTR5.2.1) GB00BMCLYF79 0 2710652 0.000000 22.006560 Sub Total 8.A 2710652 22.006560%

8B1. Financial Instruments according to (DTR5.3.1R.(1) (a))

Type of Expiration Exercise/conversion Number of voting % of voting financial date period rights that may be rights instrument acquired if the instrument is exercised/converted Sub Total 8.B1

8B2. Financial Instruments with similar economic effect according to (DTR5.3.1R.(1) (b))

Type of Expiration Exercise/conversion Physical or Number of % of voting financial date period cash voting rights rights instrument settlement 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 Name of controlled % of voting % of voting Total of both controlling undertaking rights if it rights through if it equals or person equals or is financial is higher than higher than instruments if the notifiable the notifiable it equals or is threshold threshold higher than the notifiable threshold Wilhelm K.T. Zours Wilhelm K.T. DELPHI 5.183174 5.183174% Zours Unternehmensberatung Aktiengesellschaft Wilhelm K.T. Deutsche Balaton 5.849398 5.849398% Zours Aktiengesellschaft Wilhelm K.T. SPARTA AG 10.973988 10.973988% Zours

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

12. Date of Completion

13. Place Of Completion

Heidelberg

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