Notice of Investor Presentation

4basebio PLC

("4basebio" or the "Company")

Notice of Investor Presentation

CAMBRIDGE, UK – 16 June 2026  – 4basebio PLC (AIM: 4BB),a company pioneering an enzymatically-produced DNA technology serving the next generation genetic medicines markets, announces that it will provide a live investor presentation on 29 June 2026.

Dr. Amy Walker, Chief Executive Officer, and Christine Wolosin, Chief Commercial Officer, will provide a live presentation via the Investor Meet Company platform on 29 June 2026 at 17:00 BST. No new material information will be disclosed during the event.

The presentation is open to all existing and potential shareholders. Questions can be submitted pre-event via your Investor Meet Company dashboard up until 28 Jun 2026, 09:00 BST, or at any time during the live presentation.

Investors can sign up to Investor Meet Company for free and add to meet 4basebio PLC via:

https://www.investormeetcompany.com/4basebio-plc/register-investor

Investors who already follow 4basebio PLC on the Investor Meet Company platform will automatically be invited.

For further enquiries, please contact:

4basebio PLC

Dr. Amy Walker, CEO

[phone]

Cairn Financial Advisers LLP (Nominated Adviser)

Jo Turner / Sandy Jamieson / Ed Downes [phone]

Cavendish Capital Markets Limited (Joint Broker)

Geoff Nash / Nigel Birks [phone]

RBC Capital Markets (Joint Broker)

Kathryn Deegan / Matthew Coakes [phone]

ICR Healthcare (Media and Investor Relations)

Mary-Jane Elliott / Jessica Hodgson [phone]

About 4basebio

4basebio (AIM: 4BB) is a Cambridge-based biotechnology company pioneering the use of synthetic DNA to enable next-generation therapeutics and vaccines. Through its proprietary enzymatic DNA synthesis platform, 4basebio produces GMP-grade synthetic DNA and mRNA with superior speed, purity, and scalability, overcoming the limitations of plasmid-based systems. The company offers application-specific DNA constructs tailored to the diverse needs of gene therapies, genome editing, mRNA production, and DNA vaccines, helping partners accelerate proof-of-concept studies and reach clinical milestones more efficiently while maintaining the highest standards of safety and quality.

For more information, visit 4basebio.com .

---

---