London Stock Exchange : Company Listings

The London Stock Exchange is the most important exchange in Europe and one of the largest in the world. It lists over 3,000 companies and with 350 of the companies coming from 50 different countries, the LSE is the most international of all exchanges.

The London Stock Exchange is comprised of two different stock markets: the Main Market and the Alternative Investment Market (AIM). The Main Market is solely for established high-performance companies, and the listing requirements are strict. Approximately 1,800 of the LSE's company listings trade on the Main Market, and the total market capitalisation is over 3,500 billion. The Alternative Investment Market on the other hand trades in small-caps, or new enterprises with high growth potential. Over 1,060 companies list on this market, with a total capitalisation of 37 billion.

Although the LSE is completely electronic different shares are traded on different systems. Highly liquid shares are traded using the SETS automated system on an order driven basis. This means that when a 'buy and sell' price match, an order is automatically executed. For securities that trade less regularly, the London Stock Exchange implements the SEAQ system which involves the market makers keeping the shares liquid.

These market makers are required to hold shares of a specific company and set the 'bid and ask' prices, thus ensuring that there is always a market for the stock.