An abbreviation for good till time; an order qualifier (specifically, time in force, TIF) whereby an order that is set to expire during an auction call phase will not be expired until after uncrossing has completed. As such, a GTT order is eligible to participate in the same uncrossing. Traders may choose to not take part in a scheduled auction by setting the expiry time very close to the scheduled start time (e.g., at least 2 seconds prior to such time).
GTT orders set to expire during a closing price crossing session (CPX) will be expired at the set time. If not, a GTT order will be expired at the end of trading day.
GTT may also denote good till triggered (a feature in orders, especially limit orders, that allows execution once the price reaches or hits a desired level).
GTT may also stand for good till trade (an alternative term for good till triggered).
