Limit Order Information System - LOIS

See: Limit Order.

Limit orders represent pre-set instructions to buy or sell an asset trading on an exchange...a stock or commodity, usually.

AAPL is trading at $190. If it reaches $185, you think it's a good deal. So you set a limit order to buy 1,000 shares at $185 a share.

If the stock goes up, the limit order never goes into effect. If it only drops to $187, the order still doesn't execute. But a drop to $185 and your broker will automatically close the deal.

The Limit Order Information System keeps a tab on all these potential orders. It's an electronic system that market specialists use to track the stock market. The LOIS helps them find the best prices on the various exchanges.