Capital markets – LSE’s updated rules for UK AIM market

The London Stock Exchange's revised framework, in force immediately, cuts admission burdens and aims to assist fundraisings and acquisitions

The London Stock Exchange (LSE) has confirmed the changes to its rules for AIM companies and has published an updated copy of the AIM Rules for Companies.

The change follows the LSE's earlier consultation (see our blog post here) and intends, amongst other things, to reduce unnecessary regulatory burdens on admission and support AIM companies undertaking transactions.

The new rules, which are as consulted on (with some minor amendments), came into force on 5 August 2026.

Key changes in the new rules include:

• Working capital statement no longer required – The requirement to produce a working capital statement has been replaced with a requirement to disclose details of the company's capital resources and financial obligations, together with details of future fundraising needs.
• Accepted accounting standards expanded – UK incorporated companies are now allowed to use UK GAAP instead of IFRS (a policy approach that was already being applied in practice).
• Incorporation by reference permitted – There is not an exhaustive list of the information that can be incorporated by reference into an AIM admission document, but the company, supported by its nominated adviser, must assess whether incorporation by reference is appropriate.
• Capital access window introduced – Companies undertaking an equity fundraise are now able to voluntarily request a suspension, which the LSE will consider via the company’s nominated adviser on a case-by-case basis.
• Acquisitions– Various changes have been made to the rules on acquisitions, including: 
  • allowing a nominated adviser to request that an AIM company is not suspended upon announcing a reverse takeover in contemplation (again, a policy approach that was already being applied in practice); and 
  • allowing an acquisition not to be treated as a reverse takeover solely because it exceeds 100% in the class tests, if there is not a fundamental change to the company’s business, board and/or voting control. 

The LSE has also made some clarificatory amendments to its rules for nominated advisers, as consulted on, which aim to reinforce the nominated adviser role as a valuable resource for AIM-listed companies. The updated AIM Rules for Nominated Advisers also took effect on 5 August 2026.