Time-in-Force
Understand crypto time-in-force instructions including GTC, IOC, FOK and GTD, with fill behaviour, cancellation and execution trade-offs.
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Time-in-force (TIF) tells the venue how long an order may remain active and what to do with unfilled quantity. It changes order lifecycle, not the underlying price instruction.
Price instruction and duration instruction are separate
A limit price defines the acceptable execution boundary. Time-in-force defines persistence and fill conditions. For example, the same buy limit at £80,000 can be GTC and rest for days, IOC and cancel unfilled quantity immediately, or FOK and require the entire quantity to execute immediately.
TIF therefore controls order state rather than expressing a bullish or bearish view.
Common time-in-force instructions
| TIF | Typical meaning | Partial fill? | Unfilled remainder |
|---|---|---|---|
| GTC — Good-Til-Cancelled | Remain active until filled or cancelled | Yes | Stays live |
| IOC — Immediate-Or-Cancel | Execute available quantity immediately | Yes | Cancelled immediately |
| FOK — Fill-Or-Kill | Entire quantity must execute immediately | Normally no | Whole order cancelled if full fill unavailable |
| GTD/GTT — Good-Til-Date/Time | Remain active until specified expiry | Yes | Cancelled at expiry |
Match TIF to execution objective
GTC or GTD can preserve queue position while waiting for liquidity.
IOC suits an order willing to take available size but not leave a remainder resting.
FOK avoids partial fills but can sharply increase non-execution probability.
GTD can prevent forgotten long-lived orders from remaining active indefinitely.
Changing or cancelling an order can lose queue priority. TIF choice should therefore be made before submission when queue position matters.
Worked example
The best asks contain 2 BTC at £80,000 and 1 BTC at £80,050. You submit a buy limit for 5 BTC at £80,100.
With IOC, 3 BTC can fill immediately and the remaining 2 BTC are cancelled. With FOK, if the venue determines only 3 BTC are immediately executable up to £80,100, the entire 5 BTC order is cancelled with zero fill. With GTC, 3 BTC can fill and the remaining 2 BTC can rest at £80,100.
Time-in-force in APIs and real workflows
Interfaces often hide TIF behind defaults, while APIs require an explicit code such as GTC, IOC or FOK. If an automated client omits the field, the venue default can leave an order resting when the strategy expected immediate cancellation.
Expiry-based orders also need clock discipline. A good-till-date instruction depends on the venue's accepted timestamp format and server clock, not merely the trader's local computer time. For systems using GTD/GTT, record the exact expiry returned by the venue acknowledgement.
Common mistakes and misunderstandings
- Leaving GTC orders active and forgetting they still represent executable intent.
- Using FOK when partial execution would have been acceptable, creating unnecessary non-fills.
- Assuming IOC means no partial fills—it explicitly allows them.
- Assuming TIF changes the limit price or guarantees execution quality.
- Not checking whether a venue interprets expiry time in UTC or another timestamp convention.
Knowledge checkpoint
Q1. What happens to the unfilled remainder of an IOC order?
Q2. How does FOK differ from IOC when only 60% of the requested size is immediately available?
Q3. Why can GTC create operational risk even when the limit price is correct?
Q4. Does time-in-force change the worst acceptable limit price?
FAQ
❓ What is the default time-in-force?
Many venues default limit orders to GTC, but this should be checked rather than assumed.
❓ Does IOC mean immediate full execution?
No. IOC can partially fill immediately and cancels the rest.
❓ Does FOK allow partial fills?
Its purpose is normally full immediate execution or none, subject to venue-specific implementation.
❓ Can a GTD order expire while partially filled?
Yes. The filled portion remains executed and the remaining quantity is cancelled at expiry.
Summary
- Time-in-force controls persistence and handling of unfilled quantity.
- GTC, IOC, FOK and GTD express materially different lifecycle rules.
- The same limit price can produce very different outcomes under different TIFs.
- Venue support and exact semantics should be verified before use.
This building block explains execution mechanics and risk. It is not a recommendation, signal or instruction to trade any cryptoasset.
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