And it seems many have been quick off the mark to buy such stocks, or to “Bed & ISA” their existing holdings (sell and repurchase shares within their ISA wrapper).

On Monday – the first day AIM shares became ISA eligible investments – The Share Centre saw a 164% increase in AIM stock purchases.

Meanwhile, trading platform Interactive Investor saw a 300% climb in AIM purchases and trades within ISA wrappers rose nearly 40%.

The Share Centre said the five most popular AIM-listed purchases on the first day were Fastjet, Sirius Minerals, Monitise, GLOBO, and IGas Energy.

Data from Hargreaves Lansdown showed that minerals and mining stocks dominated on the first day.

Gavin Oldham, chief executive at The Share Centre, said: “ISA-wrapped AIM investment is off to a flying start. We’ve seen an excellent early appetite from investors looking to take advantage of the new tax efficient way to invest in AIM stocks.

“As the new eligibility becomes more widely known, and AIM stocks take their rightful place as a key component of the average investors’ portfolio, AIM investment will pick-up a head of steam, supporting the growth of the UK’s small but expanding companies.”

Elsewhere, research by Barclays Stockbrokers suggested a strong investor appetite for AIM shares.

The poll found that an overwhelming 84% of respondents will invest in these shares within their ISA.

Investors surveyed were most interested in investing in Oil and Gas (30%) and Information Technology (21%) – followed by healthcare and industrials (each with 10% of the vote).

However, investing in AIM shares comes with its risks.

Ben Yearsley of stock broker Charles Stanley Direct said although the surge in demand for AIM stocks will be great news for small business, it may not be the right thing for every investor.

He said: “The Treasury hopes these new measures will encourage investment in small businesses, but is it a good idea to use your ISA allowance to invest in AIM shares? Certainly AIM is home to some exciting, dynamic companies with significant growth potential. In an ISA any profits made would be tax free, but with AIM companies there is also a high risk you can lose a substantial part of your investment, even all of it, if the company you choose struggles or fails altogether. In addition, shares are typically less frequently traded than on the main London market, which means changes in price can be more dramatic and there can be a wide gap between buy and sell prices.

“So, while the new rules are good news for ISA investors as it expands the range of permitted investments, the volatile and high risk nature of AIM shares means they are usually suitable only for more sophisticated investors who understand the risks and can accept large capital losses. Such losses when arising within an ISA are not then able to benefit from normal Capital Gains Tax loss reliefs.”

Yearsley said investors who are interested in AIM companies but want to add an extra risk buffer to their portfolios should consider funds investing in the AIM market.