The Unlisted Securities Market (USM), which ran from 1980 to 1996, was a stock exchange set up by the

London Stock Exchange London Stock Exchange (LSE) is a stock exchange in the City of London, England, United Kingdom. , the total market value of all companies trading on LSE was £3.9 trillion. Its current premises are situated in Paternoster Square close to St P ...

to cater for companies too small to qualify for a full listing. The USM allowed companies to be traded which did not have the full three year trading history required by the main market, or which wished to float less than 25 percent of their share capital. The USM allowed as little as 10% to be floated. The

Alternative Investment Market AIM (formerly the Alternative Investment Market) is a sub-market of the London Stock Exchange that was launched on 19 June 1995 as a replacement to the previous Unlisted Securities Market (USM) that had been in operation since 1980. It allows ...

(AIM) was set up in June 1995. The USM no longer accepted new introductions, and companies which were already quoted on the USM had twelve months to decide either to move the quotation to AIM, or to delist.

References

* * {{Investment-stub Stock exchanges in the United Kingdom London Stock Exchange