Order matching system

An electronic order matching system matches buy and sell orders for a security on a stock market, a commodity on commodity market or matching other types of electronically traded financial instruments such as futures contracts.

Electronic order matching was introduced in the early 1980s in the United States to supplement open outcry trading (for example the then Mid West Stock Exchange (now the Chicago Stock Exchange) launched the "MAX system, becoming one of the first stock exchanges to provide fully automated order execution" in 1982).

Large limit orders can be "front-run" by "penny jumping". For example, if a buy limit order for 100,000 shares for $1.00 is announced to the market, many traders may seek to buy for $1.01. If the market price increases after their purchases, they will get the full amount of the price increase. However, if the market price decreases, they will likely be able to sell to the limit order trader, for only a one cent loss. This type of trading is probably not illegal, and in any case, a law against it would be very difficult to enforce.

Orders are usually entered by members of an exchange and executed by a central system that belongs to the exchange. The algorithm that is used to match orders varies from system to system.

In modern trading, the order matching system is often part of a larger electronic trading system which will usually include a settlement system and a central securities depository. These services may or may not be provided by the organisation that provides the order matching system.

See also

• Open outcry
• Electronic communication network
• Alternative trading system
• Multilateral trading facility