Director Dealing

16 February 2026

4basebio PLC

("4basebio" or the "Company")

Director Dealing

Cambridge, UK, 16 February 2026  – 4basebio PLC (AIM: 4BB), an innovation driven biotechnology company enabling and accelerating development of advanced therapy medicinal products (ATMPs) through its high performant GMP-grade synthetic DNA products, announces that on 13 February 2026 it was informed that Dr. Amy Walker, Chief Executive Officer of the Company made the following purchase in ordinary shares in the capital of the Company through the market.

Further details are set out in the Notification of Dealing Form below.

Director / PCA	Number of Ordinary Shares Acquired	Purchase Price (Aggregated) (p)	Shareholding Following Acquisition	Shareholding Following Acquisition as a Percentage of Issued Share Capital
Dr. Amy Walker	2,650	586.08	46,666	0.30%

The 2,650 shares purchased represent approximately 0.02 per cent. of the Company's issued share capital.

The issued share capital of the Company comprises 15,538,518 ordinary shares.

This announcement contains inside information for the purposes of Article 7 of EU Regulation 596/2014 as amended by regulation 11 of the Market Abuse (Amendment) (EU Exit) Regulations 2019/310.

For further enquiries, please contact:

4basebio PLC	[phone]
Dr Amy Walker, CEO
Cairn Financial Advisers LLP (Nominated Adviser )	[phone]
Jo Turner / Sandy Jamieson / Ed Downes
Cavendish Capital Markets Limited (Joint Broker)	[phone]
Geoff Nash / Nigel Birks
RBC Capital Markets (Joint Broker)	[phone]
Kathryn Deegan / Matthew Coakes ICR Healthcare (Media and Investor Relations) Mary-Jane Elliott / Jessica Hodgson	[phone]

Notes to Editors

About 4basebio

4basebio (AIM: 4BB) is an innovation driven life biotechnology company focused on accelerating the development of advanced therapy medicinal products (ATMPs) through its high-performance synthetic DNA products and non-viral, cell targeting nucleic acid delivery platform. The Company’s objective is to become a market leader in the manufacture and supply of high-quality synthetic DNA products for research, therapeutic and pharmacological use as well as development of target specific non-viral vectors for the efficient delivery of payloads in patients.

Forward-looking statements

This announcement may contain certain statements about the future outlook for 4basebio.  Although the directors believe their expectations are based on reasonable assumptions, any statements about future outlook may be influenced by factors that could cause actual outcomes and results to be materially different.

Notification and public disclosure of transactions by persons discharging managerial responsibilities and persons closely associated with them

1	Details of the persons discharging managerial responsibilities / person closely associated
a)	Name	Dr. Amy Walker
2	Reason for the notification
a)	Position/Status	Chief Executive Officer
b)	Initial notification/ Amendment	Initial notification
3	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	4basebio plc
b)	LEI	213800E2DX9EAIUNCB30
4	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted
a)	Description of the financial instrument, type of instrument Identification code	Ordinary Shares ISIN: GB00BMCLYF79
b)	Nature of the transaction	Acquisition of ordinary shares
c)	Price(s) and volume(s)	Price(s) Volume(s) 586.08p 2,650
d)	Aggregated information -      Aggregated volume -      Aggregated Price	2,650 586.08p
e)	Date of transaction	13 February 2026
f)	Place of transaction	London Stock Exchange

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