Attach no time instruction and your order is a day order, which means it is good only during the trading day it was entered, generally cancels at the end of regular trading hours, and does not carry over to the extended-hours session or the next trading day. FINRA puts those regular hours at 9:30 a.m. to 4 p.m. Eastern Time. The condition that changes the answer is the instruction you attach instead, and the five common ones differ on two things only: how long the order lives, and what happens to the shares that do not fill.
Day orders end with the regular session
A day order is the default because the rulebook treats silence as a choice, and the SEC's order-types bulletin, updated 18 August 2026, says so directly. Unless an investor specifies a time frame for the expiration of an order, orders to buy and sell a stock are day orders.
The end of the session is a hard stop, not a pause. An unexecuted day order does not reappear the next morning at the same price, and it does not follow the stock into extended hours. Day orders, if not executed, generally cancel at the end of regular trading hours of the trading day that they are entered. Re-entering it the next day is a new order at the back of a new queue.
GTC runs until the firm's own limit, not forever
A good-til-canceled order lasts until it is executed in full or it is canceled, and the time limit an investor can leave one open varies by brokerage firm. "Canceled" includes cancellation by the firm. FINRA describes GTC orders as remaining in effect until they are executed by the brokerage firm or canceled by the customer, and the firm's own expiry policy sits on top of that.
Two mechanical consequences follow. A GTC limit order left at a price the stock reaches months later still executes, at the size you set months earlier. And a resting GTC order is priced against a market that has moved on, so the reason it finally trades has nothing to do with what you knew when you entered it.
IOC, FOK and AON decide the unfilled remainder
These three are not durations so much as rules about leftovers.
An immediate-or-cancel order must be executed immediately, and any portion of the order that cannot be filled immediately is canceled. Partial execution is allowed; the remainder is not held.
A fill-or-kill order must be executed immediately in its entirety, and otherwise the entire order is canceled, with no partial execution allowed. It is an all-or-nothing instruction with an immediate deadline.
An all-or-none order must be executed in its entirety or not executed at all, and unlike a fill-or-kill order it remains active until it is executed or canceled. Same completeness rule, no immediacy rule.
Two more sit alongside them. An on-open order must be executed when the market opens or re-opens, and an on-close order at the closing price, with any balance not executed as part of that trade canceled.
The five conditions side by side
Scroll sideways to see the full table →
| Condition | How long it lives | Partial fill allowed |
|---|---|---|
| Day | Until the end of regular trading hours that day | Yes |
| GTC | Until executed in full or canceled, within the firm's limit | Yes |
| IOC | Immediate only | Yes, remainder canceled |
| FOK | Immediate only | No, entire order canceled |
| AON | Until executed or canceled | No |
Example: 500 shares with only 300 available
An example, and a mechanism rather than a strategy; the 500-share order and the 300 shares available are fictional, since no public figure fixes a specific order book depth. A buy limit for 500 shares at $20.00 reaches the market, and 300 shares are available at $20.00 or lower.
As a day order, 300 shares fill for 300 times $20.00, or $6,000, and the remaining 200 stay open until regular trading hours end at 4 p.m. Eastern, then cancel. As a GTC order, the same 300 fill and the same 200 stay open past the close, subject to the firm's own time limit on GTC orders. As an IOC order, 300 fill and the 200 cancel at once. As a fill-or-kill order, nothing fills, because no partial execution is allowed and the entire order is canceled. As an all-or-none order, nothing fills either, but the full 500 stays active waiting for a moment when all 500 are available.
Five instructions, one market, five different records. The 200-share remainder is the whole story, which is why what a partial fill does to your position is the mechanic to read next, and why the choice between a market and a limit order sets up this decision in the first place. The waiting has no regulatory backstop either: no SEC regulations require a trade to be executed within a set period of time, so an order's own condition is the only deadline it has.
Source references
Primary sources used for this guide. Follow the links for the original scope, definitions and conditions.
- Understanding Order Types – Investor BulletinAccessed 2026-09-17
- Order TypesAccessed 2026-09-17
- Trade Execution: What Every Investor Should KnowAccessed 2026-09-17