DEFINITION of 'Locked Market'
A market in which a stock's bid and ask prices are identical. In a locked market, there is no bid-ask spread; normally, there is a difference between the highest price a buyer will pay for a security and the lowest price a seller will accept. Locked markets are unusual and typically short-lived.
BREAKING DOWN 'Locked Market'
In a locked market, it may be necessary for exchanges to halt automatic order execution and implement manual order execution because executing orders in a locked market is prohibited. Securities and Exchange Commission regulations require national exchanges to not even display quotes that indicate a locked market. The SEC considers a locked market to violate fair and orderly market rules, which requires that buyers and sellers receive the next and best available prices when trading securities.