NEW YORK ( TheStreet) -- The London Stock Exchange's Alternative Investment Market - home to small growth companies - celebrated its 20th anniversary this week. 

David Battersby, investment manager at Redmayne-Bentley, said one of AIM's biggest achievements is its ability to draw in large amounts of money, providing opportunities for the companies to grow.

"When it started twenty years ago, you have to bear in mind, none of the companies then are actually still there now," said Battersby. "Many of them have actually moved on to the main list and certainly as the Alternative Investment Market has grown, it's regulation has been considered worthy enough for many large companies to consider staying on AIM."  

Battersby said one of the great advantages of the Alternative Investment Market is tax incentives.

Companies that are part of the Alternative  Investment Market are traded on the London Stock Exchange, but not listed on the exchange. 

According to the London Stock Exchange website, AIM is "the world's most successful growth market."

Since its launch in 1995, over 3,600 companies from around the world have chosen to join AIM.

Batterbsy said one major success story from AIM is retailer Asos, which is an online beauty and fashion store, and the largest company on the index.

In a written piece on AIM, Battersby noted that when Asos floated its shares on the London Stock Exchange in 2001, it raised $2.3 million pounds, valuing the company at $12 million pounds.

Battersby noted that during the past 20 years "AIM has built a reputation for supporting fledgling companies and innovation as an alternative to the main market."

He added, "reports by both left and right-wing think tanks have said investing in smaller companies benefits the UK economy. Therefore it is seen as a good thing to provide tax benefits to encourage people to invest in AIM-traded companies and I see no reason why this will change in the future."

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