Define a time stop and signal expiry before entering

Separate three clocks

Signal expiry is the absolute time after which the original opportunity no longer authorizes exposure under the chosen rule. Maximum holding time limits elapsed duration from a specified event, such as the first confirmed entry fill. Order time in force controls how long an unfilled order remains eligible. Expiring or canceling the original entry order does not close units already bought.

For the hypothetical policy here, start the holding clock at the first entry fill, retain the original signal expiry, and request closure when the earlier deadline is reached. Later partial fills or position updates do not restart either clock. If no entry has filled by expiry, cancel the remaining entry request and reconcile whether a fill raced with cancellation. These are chosen policy rules, not universal optimal horizons.

A deadline requests an action; it does not prove an exit

Record the deadline, decision timestamp, submitted instruction, confirmed fills and final flat-state evidence. At expiry, prevent further exposure from the same signal and reconcile competing entry or exit orders under the venue’s rules. Simply setting a signal flag to expired, canceling an entry order or receiving an exit acknowledgement does not establish a flat position.

Include costs for the actual holding interval, including any funding settlement crossed before the exit really fills. Compare candidate time rules only on the same predeclared opportunities with their respective executable outcomes, including losing and unresolved cases. Changing a deadline after watching price linger converts that observation into rule development; it does not validate a better exit.

A 09:19 deadline precedes the signal’s 09:20 expiry

Use a fictional linear market on one UTC day. A signal recorded at 09:00 expires at 09:20. The first and only entry fills five units at 100 at 09:04, and the maximum holding time is 15 minutes from that fill. The exit-request deadline is therefore min(09:20, 09:19) = 09:19. The illustrative stop at 97 and target at 104 are not reached before the scenarios below close.

In the correctly executed scenario, a timer requests the exit at 09:19 and all five units fill at 100.20 at 09:19:02. Gross P&L is 1 USDT. Entry and exit fees at an illustrative 0.05% are (500 + 501) × 0.0005 = 0.50050, leaving 0.49950 net. Define a hypothetical funding settlement at exactly 09:20 that charges this five-unit long 0.30 if still open. The correctly closed position does not pay it.

In a separate faulty-implementation scenario, the timer only attempts to cancel the old entry request and never submits an exit. The five units remain open across settlement, pay 0.30 and finally close at 99.60 at 09:24. Gross P&L is −2; execution fees are (500 + 498) × 0.0005 = 0.499. Net P&L is −2.799. Attempting to cancel an already filled entry order did not undo the position.

The two scenarios demonstrate compliance and an implementation defect under invented fills. They do not establish that 15 minutes is a profitable horizon or that waiting always worsens the result. A compliant exit could also receive a worse fill. Keep the original rule version and distinguish execution failure from the rule’s economic performance.

A late entry does not renew an expired idea

With the same absolute 09:20 signal expiry, an entry first filled at 09:12 would have a holding-clock deadline of 09:27 but still an exit-request deadline of 09:20. Starting a new full 15-minute allowance at each partial fill would silently change the policy. Likewise, after a timed exit an automated system must not immediately recreate the same exposure from an unchanged expired signal. A later re-entry requires whatever new-opportunity rule was specified in advance.