What the new AIM rules mean – the biggest changes in two decades
Responding to the demands of listed companies, investors, the Quoted Companies Alliance (“QCA”) and other stakeholders, the London Stock Exchange (“LSE”) published a revised version of the AIM rules on 5 August 2026. These new AIM rules have been designed so that the AIM market can better support founders, innovative growth companies and investors by making it easier for newer entrants to join and to reduce the burden on those already listed.
Reduced procedural frictions at admission, increased flexibility around fundraising and acquisitions, and a clearer emphasis on investors’ responsibility are likely to be attractive developments for many growth companies.
For CFOs, however, fewer formal requirements do not remove the need for robust forecasting, controls, disclosure, and investor-ready financial information. If anything, strong financial credibility may become even more important with greater emphasis on company-led disclosures and investor judgement.
The most significant changes for companies
The below summarises the key changes of most relevance to companies already listed on AIM and those looking to list on AIM in the future:
1. Accounting Standards: Greater accounting flexibility
The option to use UK GAAP should offer lower costs as a potentially complex conversion to IFRS is no longer necessary and there would be reduced demands on finance team and other internal resources.
The choice of the most appropriate accounting framework will still depend on investors, group structure, comparability and future ambitions. IFRS may remain the accounting framework of choice for some, especially for those looking to list on the Main Market in the future. Additionally, many investors are likely to be more familiar with IFRS standards, which may encourage businesses to continue to adopt this framework.
Those companies that are not incorporated in the United Kingdom or a European Economic Area country must prepare and present their accounts in accordance with either:
- International Accounting Standards;
- US Generally Accepted Accounting Principles;
- Canadian Generally Accepted Accounting Principles;
- Australian International Financial Reporting Standards (as issued by the Australian Accounting Standards Board); or
- Japanese Generally Accepted Accounting Principles
However, these companies may apply to the LSE 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.
2. Admission documents: Working capital statement no longer required
The requirement for working capital statement within the Admission Document has been removed and replaced by a more targeted disclosure of:
- Available capital,
- Liquidity,
- Financial obligations, and
- Expected fundraising needs over the next 12 months.
Companies will still need to demonstrate that their financial resources, obligations and funding plans are robust and supportable. Whilst the bureaucracy may be reduced somewhat, the impetus will remain on the company itself to prove they are IPO-ready to the market and its potential investors.
3. Substantial transactions threshold rises
The class-test threshold for a substantial transaction has increased from 10% to 25% which means acquisitions and disposals below the new threshold no longer require AIM Rule 12 announcements.
For acquisitive businesses, the higher threshold should reduce regulatory friction for certain transactions as the previous threshold for many AIM Companies captured routine transactions, potentially allowing management teams to focus more on execution and strategic rationale.
4. Reverse takeovers
Perhaps the most commercially significant amendment and the one that will support acquisition activity by AIM companies.
Under the new rules an acquisition exceeding 100% under the class tests will not constitute a reverse takeover where it does not represent a fundamental change in business, board and/or voting control. Instead these types of transaction will be labelled as substantial transactions and shareholder approval may still be required.
5. Fund raising – New ‘’Capital Access Window’’
The challenge of price volatility during a fundraising process has been made simpler by companies now being able to access Capital Access Windows. An AIM company can now apply to the LSE for a temporary suspension to allow it to approach a broad investor base (including retail) without the risk of price volatility.
Whilst the LSE has not prescribed a minimum or maximum period for the Capital Access Window the expectation is that companies will want to keep them to a relatively short duration and have their shares trading again as soon as possible.
6. Express Market route and Dual market applicant 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.
Eligibility for the Express Market route involved having traded on a qualifying market for at least three years, ensuring that there has been no fundamental change of business or Board in the preceding 12 months and to have a proposed market capitalisation of at least £20m.
For a company looking at the dual market applicant route companies must raise at least £6m as part of the IPO in order to rely on a single admission document for both markets.
Separately certain Main Market applicants with an establisged public market track record benefit from an accelerated admission process on to AIM.
This reform simplifies the process, and reduces duplication in the admission process. For eligible companies, this means faster and, cheaper admission onto AIM. This also presents a great opportunity for international businesses looking to expand their reach into the UK.
7. “Buyer beware” positioning
Admission documents now need to make AIM’s buyer-beware model more prominent (on the first page of the Admission Document), reinforcing investor responsibility for diligence. The company still needs clear and balanced disclosures within their Admission Document for potential investors to make reliable decisions. Credibility may matter even more where investors are reminded to challenge the proposition.
8. 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. Instead, companies can consider a recognised code as a framework and disclose their approach to the roles and responsibilities of directors, risk and controls, board composition, investor relations and remuneration and performance.
This amendment seeks to ensure that AIM companies have the flexibility to adopt governance arrangements which are appropriate to their size, stage of development and circumstances.
9. Incorporation by Reference
AIM companies may now incorporate certain information by reference into their Admission Documents in accordance with the new guidance to the relevant AIM rules. The benefit for CFOs of this change is the reduced length and cost of preparing Admission Documents.
10. 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:
- Intra-group transfers;
- Transfers between spouses or into a pension plan; and
- Sales in the event of financial hardship
Clarity has also been provided that lock-in arrangements are contractual between the company and the relevant parties, and the LSE has no authority or power to enforce compliance with such arrangements,
11. Nominated Adviser Role and Disclosure
The new AIM Rule 11 requires an AIM company to be properly engaged with its NOMAD so that the NOMAD can provide specialist advice particularly around:
- Changes and developments that may reasonably have a material impact on its business and/or prospects; and
- Whether any changes and developments to its business and/or prospects are likely to have a market impact, and the company’s disclosure obligations under MAR.
This new rule places more onus on the AIM company to ensure that it has sufficient systems, controls, resources and procedures in place to enable them to identify and monitor any such changes and developments.
New AIM Rule 11 also removes the obligation to disclose price-sensitive information in order to remove the overlap with The Market Abuse Regulations.
Closing thoughts
The new AIM rules remove unnecessary complexity and better align the regulatory framework with the needs of a modern growth market whilst ensuring that investor confidence is maintained. HaysMac welcomes the new rules which have come into immediate effect and recognises that the changes that have been made provide exciting opportunities for those looking to list in the future as well as those already on the market. These rule changes are an important step in securing the future of AIM.
Wondering what the new rules mean for you and your business? Our Equity Capital Markets Team is on hand for support and advice. Get in touch to find out more via the link below.
