This is definitely a testable question on the Series 57 exam. The timely reporting of transactions is critical for market integrity. All transactions are required to be reported as soon as practicable, but not later than 10 seconds after execution . If a transaction is executed and later cancelled under FINRA trade reporting rules the firm is required to report the transaction promptly. The trader is then required to use the ACT trade scan to cancel the transaction. The trade cancellation report should be made on the same day as the trade was reported provided the trade reporting facility is still open. This rule is in effect for transactions executed during normal business hours as well as for those trades executed during extended hours trading.