As investors in London’s junior AIM market know only too well, high risk does not always mean high return. Now, more than ever, the Alternative Investment Market of the London Stock Exchange needs to prove that it can offer investors high-quality companies.******The FTSE Small Cap index of smaller companies listed on the main London market has outperformed the AIM 100 index on the way down, and on the way back up. The FTSE Small Cap has gained almost 30 percent over the last couple of months, while the AIM 100 has risen 20 percent.******And that’s after the AIM 100 saw falls of over 50 percent in the past year, much more than the 27 percent posted by the FTSE Small Cap index.******While liquid companies like Advanced Medical Solutions and Cape typify the benefits of AIM, there are too many that have cut back so much that they are reduced to a CEO operating alone out of his spare bedroom.******AIM officials said on Friday that they thought the market has had its best month for a year, raising around 500 million pounds for companies, but this includes 220 million pounds raised by one company alone, Max Properties.******Fund managers say that they like some AIM companies that are making profits, or close to that point. However high-risk beta stocks that expect investors to hang around for five years or more should be happy that the winter weather has cleared, because they’re likely to spend most of their time with their caps in their hands.******If AIM wants to see its companies grow fruitfully as cash returns to the market, it will have to start out by sifting the chaff from the wheat.