AIM (London Stock Exchange growth market)
The London Stock Exchange's market for smaller and growing companies. You sell shares to public investors and your shares can then be traded, in return for ongoing rules, costs and scrutiny.
- Shares
How it works
AIM is run by the London Stock Exchange under its own AIM Rules for Companies, which were substantially rewritten on 5 August 2026.
- You must appoint a nominated adviser (nomad), who assesses whether your company is appropriate for AIM, manages the admission and advises you on the rules. You must keep a nomad at all times. If you lose yours and do not replace it within 6 weeks, your shares are removed from AIM.
- You must also keep a broker at all times. The broker markets your shares to investors and must be authorised by the FCA.
- You publish an admission document describing the company. A reporting accountant reviews your financial records, and lawyers prepare the legal documents.
After admission you must publish half-yearly reports within 3 months of the period end, audited annual accounts within 6 months of the year end, and details of your approach to corporate governance, and pay AIM fees.
Upsides and downsides
Upsides
- Raise money from a wide range of investors, and raise more later
- Shares that can be traded, which can help owners and staff sell shares in future
- A higher profile with customers, partners and investors
- Founders can often keep control, depending on how many shares they sell
- Fewer requirements than the Main Market
Downsides
- Expensive to join and to stay on, every year
- Detailed public reporting, with results published every 6 months
- Your share price is public and can fall for reasons outside your control
- Major transactions may need shareholder approval
Risks
- If you lose your nominated adviser and do not replace it within 6 weeks, your shares are removed from AIM
- A thinly traded share price can make future fundraising harder
- Shareholders can push for changes to the board or strategy
What it costs
- How it is priced
- Shares sold to public investors, plus adviser, broker and AIM fees
- Costs that are easy to miss
- Fees for the nominated adviser, broker, reporting accountants and lawyers to join
- Ongoing nomad, broker, audit and AIM fees every year
- Management time spent on reporting, investor relations and compliance
The AIM Rules set no minimum amount for trading companies. Investing companies must raise at least £6 million. British Business Bank guidance says AIM companies often raise between £1 million and £50 million.
Have an offer? Dilution calculator: see what you would own after each round
Does it fit?
Could fit when
- You are a growing company that needs substantial capital, and expects to need more
- You can bear the costs and management time of being a public company
- You want your shares to be tradeable
Unlikely to fit when
- You are a small business, or your need could be met by private investors or debt
- You do not want public reporting and scrutiny
- Your management team cannot take on public-company duties
Who can use it
- Business types: Public limited company
- You must appoint a nominated adviser and keep one at all times
- You must keep a broker at all times
- You must publish an admission document, unless you are joining from certain other markets by the express route
- If your business has not been independent and earning revenue for at least 2 financial years, related parties and applicable employees must agree not to sell their shares for 12 months after admission
Am I ready?
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- Nominated adviser lined up
- Audited financial history
- A public-company board
Regulation and protections
AIM is run by the London Stock Exchange under its AIM Rules for Companies. Your nominated adviser owes its duties to the Exchange, not to you. Your broker must be authorised by the FCA.
The AIM Rules changed substantially on 5 August 2026. Older guides may describe rules that no longer apply, such as the previous working capital statement and corporate governance code requirements.
Types of provider: Nominated advisers approved by the London Stock Exchange; FCA-authorised brokers; Reporting accountants and law firms.
Also consider
Sources
- London Stock Exchange: AIM · checked 7 October 2026
- London Stock Exchange: AIM Rules for Companies (August 2026) · checked 7 October 2026
- British Business Bank: What is the Alternative Investment Market (AIM)? · checked 7 October 2026