The London Stock Exchange will expand trading.

The London exchange said it is merging with a group of international securities dealers to form a 24-hour electronic marketplace for stocks, a venture that would compete with exchanges worldwide. The exchange said it would change its name to the International Stock Exchange after merging with the International Securities Regulatory Organization. The ISRO is the self-regulatory body for about 200 firms in the Eurobond market and also deals in over-the-counter trading in leading international securities, including more than 100 blue-chip American stocks.