Good Til‘ Cancelled Order Definition. A Good ‘Til Cancelled Order, or "GTC" or "Open Order", is a customer‘s order given to their forex broker to buy or sell a currency or security, usually at a particular price, that remains in effect until executed or cancelled. If the GTC order remains unfilled after a long period of time, a broker will usually confirm that the customer still wants the transaction to occur. Sometimes a broker will stipulate in the type of plan that you choose whether they can cancel a GTC after 30 to 90 days, after which time they will contact you about reinstatement or will cancel it outright. Typically, a forex trader or investor will use a GTC to set a price target at which to sell that is far away from its current price point. The investor can always cancel the order at any time.