A type of order comprising several limit orders for several companies, but in the event that one gets filled, the rest are canceled. This type of order allows a trader to buy one out of a number of potential stocks at the best price in the shortest amount of time.
For example, a trader might use a one-cancel-all order if he or she has $5,000 to invest in the market and wants to put it all in one company but has several possible candidates. If the trader is looking at three stocks - ABC for $5, KLM for $20 and XYZ for $50 - the trader enters a one-cancel-all order for 1,000 shares of ABC, 250 shares of KLM and 100 share of XYZ. If XYZ is immediately filled at the $50, then the other two orders are canceled and will not be filled.