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An order to conduct two transactions such that, if one transaction is done, then the other is cancelled. For example, an investor may wish to buy both stocks and bonds at a certain price. If the price becomes available for bonds first, that part of the order is filled while the order to buy stocks is cancelled. OCO orders may apply to different types of securities or even to different types or orders; for example, one may contain both stop-loss orders and limit orders. OCO orders are useful to investors who have limited funds and perhaps are unsure about the market's direction at a given time. It is also called an either-or order.
See alternative order.