An evaluation attempted of both the development of the Third Market in the London Stock Exchange and its comparison with junior markets in other major stock exchanges. The Third Market provided access to the capital markets and to a trading market for a spectrum of young companies that either had an insufficient trading record for entry to the Unlisted Securities Market (USM) or were traded off-market.For most entrepreneurs, it has always been hard to obtain both viable capital and advice. So, in the 1980s with the arrival of venture capital operations, the launch of the USM and later the creation of the Third Market broadened the potential for businessmen to obtain financial backers with good marketing. Almost ten years since submitting this research (in September 1987) as a requirement for my MSc dissertation the USM was replaced by the Alternative Investment Market (AIM). The USM no longer accepted new introductions, and companies that were already quoted on the USM had twelvemonths to decide either to move the quotation to AIM or to delist.