4basebio Plc - Holding(s) in Company

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 event changing the breakdown 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

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

13-Nov-2024

6. Date on which Issuer notified

15-Nov-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 32.764383 0.000000 32.764383 5071073 Position of previous notification (if applicable) 50.392395 0.054665 50.447060

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) GB00BMCLYF79 5071073 32.764383 Sub Total 8.A 5071073 32.764383%

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 Wilhelm K.T. Zours Wilhelm K.T. Zours DELPHI Unternehmensberatung Aktiengesellschaft 4.124958 4.124958% Wilhelm K.T. Zours VV Beteiligungen Aktiengesellschaft Wilhelm K.T. Zours Deutsche Balaton Aktiengesellschaft Wilhelm K.T. Zours SPARTA AG Wilhelm K.T. Zours SPARTA Invest AG 8.733498 8.733498% Wilhelm K.T. Zours 2invest AG 14.402185 14.402185% Wilhelm K.T. Zours Latonba AG 4.892677 4.892677%

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

15 November 2024

13. Place Of Completion

Heidelberg, Germany