AIM at 30: the best-performing AIM shares over the decades

AIM celebrates its 30th birthday on 19 June.Short-term performance has generally been poor on AIM given the tough economic conditions, but there have been better performers, such as Greatland Gold (LSE:GGP) whose share price has more than doubled since the beginning of the year. There are some even more impressive long-term share performances since AIM launched 30 years ago, and the recent troubles should not be allowed to mask that fact.

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The top two AIM performers over 20 years – accesso Technology Group (LSE:ACSO) and Judges Scientific (LSE:JDG) - are also the top two performers for the whole of the London Stock Exchange over that period. Five out of the top 10 performers and 10 of the top 20 are on AIM. The best-performing former AIM company now on the Main Market is FTSE 100 constituent Melrose Industries (LSE:MRO) with a 658% gain, making it 52nd on the list.  

There are 88 companies on AIM that have been quoted for 29 years. Not all these companies were on AIM at the start of the period and none of the top 10 performers were on AIM at the time.

Those companies have done well since moving to AIM because they have solid, long-term track records and are attractive for inheritance tax (IHT) relief portfolios. Some were family firms that would have been attracted to AIM by the IHT relief.

Over 25 years there are 124 AIM companies that have been quoted on the stock market for the full period, and again not all the companies have been on AIM for the whole period.

Only two of the top 10 over 25 years started on AIM. One is batteries and electronic components distributor Solid State (LSE:SOLI), which is one of the companies that has been on AIM the longest, having floated in June 1996 at 80p/share – the adjusted price is 20p/share. The other is gold miner Pan African Resources (LSE:PAF). They are also in the top 10 companies over 20 years.

The past two decades

Source: ShareScope on 2 June 2025. Past performance is not a guide to future performance.

There are 230 AIM companies that have been quoted for 20 years. The companies that have performed best over that time are not even at their record highs. Generally, they have consistent growth records, with some setbacks along the way, but they are not companies that had a huge one-off boost. Those companies do not tend to sustain their share price growth.

There is a wide spread of sectors included in the top 10 performers. Eight out of the 10 pay dividends and therefore the overall return is higher than the gain indicated in the table. Some have net cash positions.

Four of the top 10 performers switched from the Main Market. MS International (LSE:MSI) did not move to AIM until 22 November 2013, and the share price had closed at 176.5p the previous day. The engineer and defence equipment supplier has performed particularly strongly since late 2020 when the share price was lower than at the time it moved markets.

Airline and tour operator Jet2 Ordinary Shares (LSE:JET2) is the other one of the top 10 performers that was not on AIM for the full 20-year period. Then known as Dart Group, the company switched its listing from the Main Market to AIM on 15 August 2005, so that is nearly two decades ago. The share price was 60.25p at the time, which was lower than in April 2005.

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The share price has not got back to pre-Covid levels, but holiday business is recovering. The winter 2024-25 load fact dipped 2.2 percentage points, although most of that decline is down to the later Easter and there was a 14% increase in capacity. Canaccord Genuity believes that repurchasing convertible bonds should reduce the annual interest bill by up to £2 million.

Renew Holdings (LSE:RNWH) was known as Montpellier Group when it moved to AIM on 29 October 2001. The company was changing from a construction business to a provider of engineering services for infrastructure, and it has a solid track record.

That record has been knocked by the timing of the rail renewal programmes. Rail is nearly two-fifths of revenues. The timing of renewal spending is uncertain, and Peel Hunt reduced its 2024-25 earnings forecast by 10% to 63.6p/share. Water infrastructure demand is ahead of expectations, with further potential growth as the AMP8 capital investment period begins. The strong order book means that the long-term upward share price momentum should be regained.

Wound care company Advanced Medical Solutions Group (LSE:AMS) moved to AIM on 30 April 2002. In 2024, AMS reported a 41% increase in annual revenues to £177.5 million, including like-for-like growth of 10%. Pre-tax profit was 14% ahead at £29.4 million.

The share price has fallen following the withdrawal of a bid approach from Montagu Private Equity.

Ticketing technology developer accesso Technology Group (LSE:ACSO) started out as queuing technology company Lo-Q, and it moved from Ofex (now Aquis Stock Exchange) in 2002. It is the best-performing AIM company over 20 years with a gain of 11,300%. Growth has come from acquisitions and the broadening of the business.

The 2024 revenues were in line with guidance at $152.3 million. Pre-tax profit improved from $8.8 million to $11.7 million. Net cash was $28.7 million at the end of 2024. Transactional revenues are becoming more difficult to predict as current economic conditions could delay client decisions. There is also concern about movements in currencies.

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Judges Scientific floated as activist investor Judges Capital in 2003, although it did not commence its current strategy until 2005. The initial valuation was £2 million and, even after a period of tougher trading, it is currently valued at £500 million. That makes it one of the largest 40 companies on AIM.

Judges Scientific has built up a wide-ranging scientific instruments business via acquisitions. It has a record of successful acquisitions, something that is rarely true of acquisitive companies. There has been consistent growth in the dividend. Revenues and profit dipped last year, but that should prove a blip.

FD Technologies (LSE:FDP) changed its focus to software and recently sold its consultancy business. At the beginning of the year, £120 million of the proceeds were used to tender for shares at £19.50 each. FD Technologies has recommended a 2,450p/share bid from TA Fund XV, which values it at £570 million.

Annualised recurring revenues rose by 13% to £81.8 million in the year to February 2025. Trading was at the top end of guidance and the loss was £29.1 million.

Impax Asset Management Group (LSE:IPX) was formed when the asset management business reversed into AIM shell company Kern River on 19 June 2001 – the sixth anniversary of AIM. Impax specialises in sustainable investments and their performance has been weak in the past three years.

The latest assets under management figure shows the loss of a major St James’s Place mandate due to poor performance, but there is also a £1 billion decline from overall negative performance. By the end of March 2025, assets under management had fallen by one-quarter to £25.3 billion. Impax Asset Management says that figures for the year to September 2025 will be below expectations. There has been positive news concerning the management of a fund for BNP Paribas, which is a 13.8% shareholder in the company.

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South Africa-based gold producer Pan African Resources reported a small reduction in interim revenues from $191.1 million to $189.3 million, while profit increased by 10% to $44.6 million, but that includes a one-off Tennant Consolidated Mining acquisition gain. The strong gold price has helped the recent performance.

These top 10 companies are capable of continuing to grow, although the pace may slow.  

There are AIM companies that are capable of being strong performers over the long term. However, some of the more substantial ones are set to switch to the Main Market.

Cerillion (LSE:CER) is a highly rated telecoms billing and customer relationship management software provider that is continuing to add to its international customer base. There is potential for steady long-term growth as more clients are added, and the share price recovered following the interims.

Space and communications technology developer Filtronic (LSE:FTC) has been going from strength to strength as it wins more orders, particularly from SpaceX. A recent record of profit upgrades suggests that Filtronic could continue to do well.  

Andrew Hore is a freelance contributor and not a direct employee of interactive investor.