Time-in-Force and Special Orders

How long: day, GTC, IOC, FOK

**Time-in-force** tells the market how long your order stays alive and whether it may fill in pieces. It is the second half of a complete order ticket, and it is the half people forget. • **Day**: works until the regular session ends, then expires unfilled • **Good-til-canceled (GTC)**: works across days until filled or canceled; brokers cap it, often at 60–180 days • **Immediate-or-cancel (IOC)**: fill whatever is available now, cancel the rest • **Fill-or-kill (FOK)**: fill the entire order immediately, or cancel all of it • **All-or-none (AON)**: fill the whole amount or nothing, but unlike FOK it may wait A GTC order you forgot can fill months later, on news, at a price you would never have chosen today. Open orders are part of your risk, not part of your history.

What a long-lived order lives through

Duration is not only “how long am I willing to wait”. It is a decision about how many events you are willing to have your order survive. A U.S. stock’s year holds about 250 trading sessions, four earnings reports, four quarterly index rebalances, a dozen inflation and jobs prints and a rate decision roughly every six weeks. Every one of those is a moment when the price can move for a reason you had no view on when you wrote the ticket. That calendar is the real argument against long-dated orders. A day order exposes you to one session of news. A 60-day GTC order exposes you to about 40 sessions, a full earnings cycle, and — in a dividend payer — a corporate-action adjustment the broker may handle by cancelling the order for you, on a date you did not choose. The price that felt patient in March is a coin flip by May. The mitigation is not to avoid GTC, it is to make duration a deliberate choice with a review attached. Trade the plan, not the ticket: know which dates matter for the name you own, and cancel or re-price before them. Brokers will expire a GTC order for you on their own schedule; none of them will remind you why you placed it. One GTC ticket, one quarter of exposure — Sessions of exposure: about 60, instead of the 1 a day order gives you · Scheduled events in that window: 1 earnings report, 2 inflation prints, 2 jobs reports, ~3 rate decisions · Corporate actions that can cancel it for you: a split, a merger vote, a dividend adjustment ← · The cheapest control: cancel or re-price before each known event ← A resting order is a standing opinion about a price, and markets re-price faster than opinions change. That is why the order you forgot is the one that fills in the wrong market.

Auction orders and the rest of the board

**Market-on-open (MOO)** and **limit-on-open (LOO)** orders trade in the opening auction; **market-on-close (MOC)** and **limit-on-close (LOC)** trade in the closing auction at the official close. On NYSE and Nasdaq, closing-auction orders generally must be in by 3:50 pm ET and cannot be freely canceled after that. Lesson M11 covers how the auction finds its price. **Extended-hours** sessions usually accept limit orders only, with thinner books and much wider spreads — a market order there is how people discover that “the price” was never a single number. **Fractional-share** orders are dollar-based and typically filled internally by the broker or a wholesaler during regular hours, because exchanges trade whole shares. A complete ticket answers three questions: what instrument, what order type, and how long. “Buy 100 shares” is not a ticket — it is a wish.

The clock is part of the price

The same order sent at 9:31 and at 12:30 is not the same trade. Liquidity is not spread evenly across a session: it clusters at the open and again into the close, and it thins out in the middle of the day. Spreads follow liquidity almost mechanically — the quote is wide when few shares are being offered and narrow when they are plentiful. So duration is not bookkeeping. It is one of the three things that decide what you pay. That is why the extended-hours sessions carry a warning on every broker’s site. Pre-market and after-hours trading is a small fraction of the day’s volume, most brokers accept limit orders only there, and prices set in those sessions do **not** feed the official closing price. Late prints look like information and are mostly noise: a few hundred shares moving a quote nobody else is watching. The two auctions are the exception, because they are where the crowd actually meets. The opening auction crosses everything that accumulated overnight into a single print at 9:30, and the minutes that follow carry the heaviest volume of the day along with some of its widest spreads. The closing auction is the other large liquidity event: it sets the **official closing price**, and it exists because index funds and ETFs are measured against that number and therefore have to trade there. • **Pre-market and after-hours** — limit only at most brokers, a sliver of daily volume, spreads several times wider than midday, and no official price • **The open** — overnight orders cross in the opening auction; the first minutes trade the most shares of the day at some of the widest spreads • **Midday** — the narrowest spreads and the least volume. If your idea has no deadline, this is the cheapest hour to work an order • **The close** — the official price is set in the closing auction, where the market’s largest passive flow is required to arrive One intention, four clocks (illustrative) — Dawn a limit at 8:30 am: thin book, wide spread, no official price · Open at 9:30:01: most volume, spread near its widest of the day · Midday at 12:30 pm: narrowest spread, least volume ← · MOC, ticket in by 3:50 pm: the official price — where index money must trade ← The two prices other people are measured against are the open and the close. That is not trivia: it is why so much volume arrives in the last minutes, and why a limit price that looked generous at 11 am can be unfillable at 3:59 pm.

How partial fills change your average price

Duration decides whether an order may fill in pieces, and pieces change the number that matters: your average price. A single fill has a price. A partial fill sequence has a distribution, and the distribution is where the cost hides. Take 1,000 shares that fill in four pieces across an hour — 300 at $20.00, 300 at $20.04, 250 at $20.09 and 150 at $20.16. The VWAP of that order is about $20.06, and none of the four prints was the price you were watching. The average is the honest number, and it belongs in the journal beside the ticket rather than in your memory, which will recall the best of the four. The same arithmetic applies in the good direction: a resting limit that fills once at the top of a rally has one price, while a limit that fills in pieces on the way down has a better average than its first print. This is why the choice of duration is also a choice about price dispersion. An **IOC** order produces a single average for one instant. A **day order** that works all afternoon produces an average that is a blend of every level it met, and it may leave you partly filled with the remainder unhedged. Neither is better in the abstract — but the average is the figure to record, because a position whose entry you misremember produces a stop in the wrong place and a journal that lies. One order, four prints, one average — 300 shares at $20.00: the first print · 300 at $20.04, 250 at $20.09, 150 at $20.16: the tail — 400 shares worse than $20.05 ← · Average price for the 1,000 shares: about $20.06 · The print you will remember: $20.00 ← · The number to journal: the average, and the cost in basis points against the arrival price A partly filled order is also an unhedged position part-way through. If your size was chosen for a reason, a half-filled order is half the risk you intended and half the exposure you planned for — which is worth knowing before you decide whether to chase the rest.

The order you forgot you placed

A long-lived order does not become safer for being old, and brokers do not keep an order alive forever. Most retail GTC orders carry an internal expiry — commonly 60 or 90 days — and some cancel at the end of each quarter. An order that has silently expired looks exactly like an order that is still working, and the difference shows up only on the day you expected a fill. A resting order is also exposed to events you did not have in mind when you placed it. A **stock split** re-prices every open order, because a $400 limit on a stock that splits four-for-one is no longer a limit anyone would intend. Exchanges and brokers adjust prices and quantities on the split date, but the adjustment can leave your order far from where you meant it. The same applies to a large special dividend, a ticker change, and a merger that converts your shares into cash plus stock — in each case the order survives in form and stops meaning what it meant. Order hygiene is unglamorous, and it is where most “the broker filled me at a terrible price” stories actually come from. Before every session, read the open-orders list and cancel anything you would not place again at today’s price. An order is a live instruction, not a bookmark. The test for a resting order is simple: if it filled right now, would you be happy? If the honest answer is no, the order is not a strategy — it is a leftover.

Where the clock actually lives

Time-in-force sounds like a single property of an order, and only part of it belongs to the exchange. An immediate-or-cancel or a plain day order is a term the matching engine itself understands — the venue applies the clock. A **good-till-cancelled** instruction usually is not: most exchanges only recognise day and immediate terms, so a GTC is held by the broker and re-released each morning as a fresh day order, or managed entirely inside the broker’s own system. That difference has consequences that never appear on a confirmation. The first is queue position. An order that is cancelled overnight and re-entered at the open comes back to the end of the line at its price level, so a resting order that appeared to have sat patiently for a week may have spent every night at the back of the queue. The second is that the re-release is a moment when things can go wrong: a corporate action, a symbol change or a halt can cause the order to be cancelled rather than reinstated, and the cancellation arrives as a notice rather than as a question. The third is the calendar. On a half-day session a “day” order expires when the market closes, which is early, and a GTC released that morning can expire with it. The fourth is extended hours: whether a day order placed in the evening is held for the opening or rejected outright, and whether a GTC is eligible to work before the bell, differ by broker, and neither broker will volunteer the answer on the ticket. The practical upshot is short. Read the time-in-force table once, deliberately, and assume anything labelled good-till-cancelled is broker-managed. Where an order matters, re-place it yourself at the open rather than trusting a reinstatement you cannot see — an order you believe is working and is not is worse than no order at all, because it stops you from doing the thing that would have worked. • Day and immediate terms live at the exchange; GTC usually lives at the broker. • A re-released order loses its place in the queue every night. • Half days, corporate actions and halts can end a long-lived order without a decision from you. • Extended-hours eligibility is a broker setting, and it decides whether your order is live before the bell.

Sources

• Order types and time-in-forceInvestor.gov / SEC — Trading basics
• Closing auction order rules and cut-offsNYSE / Nasdaq — Closing auction rules
• Extended-hours trading risksFINRA — Extended-hours trading