As of Monday, companies listed on the Alternative Investment Market (AIM) can be held in an ISA wrapper.
The Share Centre saw a 164% increase in the number of AIM-listed stock purchases that day, while Hargreaves Lansdown recorded minerals and mining stocks as the most popular options. Topping the top 10 AIM shares were Amur Minerals and Berkeley Mineral Resources. The Share Centre saw increased inflows into AIM listed company Sirius Minerals.
AIM is the most successful stock market in the world in terms of growth. Since its launch in 1995 with just 10 stocks, more than 3,000 companies from all over the world have joined.
There are a number of initiatives already in place to encourage investors to take a punt on AIM companies. In order to counter the risk involved in investing in illiquid assets.
Unquoted shares are not counted as part of your estate when it comes to inheritance tax and certain AIM stocks can also qualify for a reduced rate of capital gains tax.
The stocks must be owned for at least two years to qualify, but after this AIM stocks are IHT free.
AIM investment is not for everyone however. Ben Yearsley of stock broker Charles Stanley warned about the risks of investing in unlisted companies.
"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," he said.
"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."
Mr Yearsley said that AIM shares were only suitable for the most experienced of investors.