The New AIM Rules: Key Changes for Companies

Introduction

On 5 August 2026, the London Stock Exchange (the Exchange) published a revised version of the Alternative Investment Market Rules for Companies (AIM Rules). The new AIM Rules are designed to ensure that AIM continues to support innovative and growing companies by making it easier to join AIM, facilitating acquisitions, making it easier to raise funds and giving companies greater agency over voluntary disclosure. This article summarises the key changes of most relevance to AIM companies and their advisers.

Key Changes

Express Market Route

The former AIM Designated Market route has been replaced by the new Express Market and dual-market applicant routes, which support accelerated admission for eligible international and dual-listed issuers. Eligible international issuers can access AIM as an express applicant when they have traded on a qualifying Express Market for at least three years, have not undergone a fundamental change of business or board in the preceding 12 months, and have a proposed market capitalisation of at least £20 million. A dual-market applicant route also allows companies seeking simultaneous admission to an Express Market and AIM, raising at least £6 million as part of an initial public offer, to rely on a single admission document for both markets. Separately, certain Main Market applicants with an established public-market track record benefit from an accelerated admission process.

Special Voting Shares

Applicants may now issue special voting shares at admission, subject to constitutional documents being in place which restrict who they may be held by, prevent transfer of voting rights outside such permitted group and exclude voting rights on remuneration, related-party transactions involving the holder of such special voting shares, and cancellation of admission.

Incorporation by Reference

AIM companies may now incorporate certain information by reference into their admission documents, in accordance with new guidance to the relevant AIM Rules, reducing the length and cost of preparing admission documents.

Removal of Working Capital Statement Requirement

The working capital statement requirement in admission documents has been removed and replaced with disclosure of capital resources, financial obligations and fundraising requirements for the following 12 months. 

Accounting Standards

UK-incorporated companies may prepare accounts under UK generally accepted accounting practice (Financial Reporting Standard 102) rather than International Accounting Standards. Companies not incorporated in the United Kingdom or an European Economic Area country may apply to the Exchange to use locally generally accepted accounting principles or practice, including where these are not listed in the AIM Rules, provided they are materially equivalent to International Accounting Standards and appropriate disclosures are made. Changes between standards available to a particular company will still require prior approval of AIM Regulation. 

Lock-In Arrangements

The guidance to AIM Rule 7 now permits the disposal of securities subject to lock-in arrangements within the first 12 months post-admission in three limited circumstances: transfers between spouses or into a pension plan, intra-group transfers or cases of financial hardship. It has also been clarified that lock-in arrangements are contractual as between the company and the relevant parties, and the Exchange has no authority or power to enforce compliance with such arrangements.

Class Test Threshold for Substantial Transactions

The class test threshold for substantial transactions requiring public disclosure has increased from 10% to 25%.

Reverse Takeovers

An acquisition exceeding 100% in the class tests (excluding the profits test) will no longer be automatically classified as a reverse takeover, unless it also produces a fundamental change in business, board or voting control. Such transactions will instead be treated as substantial transactions under AIM Rule 12, which may still require AIM shareholder approval. The Exchange may also determine not to suspend trading on notification of a reverse takeover in contemplation, provided the nominated adviser is satisfied that appropriate alternative disclosure can be made and has consulted the Exchange in advance. 

Capital Access Window

Companies undertaking a fundraise or a corporate transaction involving the issue of AIM securities may request a temporary trading suspension, known as a capital access window, while negotiations are conducted. There is no fixed maximum duration, though the Exchange expects windows to be short, and trading resumes once a cleansing notification confirms completion or that the transaction has been aborted.

Corporate Governance

There is no longer a requirement for companies to adopt a named corporate governance code or report on a comply-or-explain basis. Companies can instead consider a recognised code as a framework and disclose their approach to board composition, the roles and responsibilities of directors, remuneration and performance, risk and controls, and investor relations.

Nominated Adviser Role and Disclosure

The former obligation to disclose price-sensitive information, which duplicated an AIM company’s existing obligations under the UK Market Abuse Regulation, has been removed. The new AIM Rule 11 instead focuses on the nominated adviser applying its specialist public-market corporate finance experience to help the company assess the potential market impact of changes or developments in its business.

Non-Standard Director Remuneration

A nominated adviser is no longer required to provide a fair and reasonable opinion on nonstandard director remuneration where it is satisfied that the contractual terms provide reasonable commercial protections for the company, such as good leaver/bad leaver provisions or clawback. Where there is uncertainty as to whether such protections are adequate, the matter should instead be put to a shareholder vote.

Proxy Adviser Engagement

Companies may voluntarily disclose details of proxy advisor engagement by way of either a notification or on the company’s website.

Third-Party Commentary and Right of Reply

Companies may voluntarily choose to disclose their views, opinions and position in response to any third-party commentary, speculation or criticism. This seeks to address the harm that third-party commentary can cause to a company’s reputation, confidence in information, investor sentiment or share price. 

Buyer Beware

Each company will now be required to include prominent buyer-beware wording on the first page of its admission document, aligning with the buyer-beware nature of the AIM market.

The firm has extensive experience in advising companies listed on AIM and their professional advisers. Please do not hesitate to contact us if you would like to discuss further the contents of this alert.