What is a FOK (Fill or Kill) Order?

FOK (Fill or Kill)
Forex Trading Glossary

Quick Answer: A Fill or Kill order demands immediate and complete execution at the specified price, otherwise it cancels instantly—a strict condition traders use when partial fills are unacceptable.

Understanding FOK (Fill or Kill) Orders

A Fill or Kill (FOK) order demands immediate and complete execution at the requested price, or it cancels entirely. Traders use FOKs when partial fills are unacceptable—common for large orders seeking to avoid execution slippage.

When to Use FOK

Institutional traders might deploy FOK orders to capture fleeting arbitrage opportunities or to protect against spreading risk across multiple fills. Retail traders can use FOK when liquidity is thin and they only want the trade if full size executes instantly.

Execution Discipline

Pair FOK orders with strong depth analysis. If depth is inadequate, the order will simply cancel—avoid chasing the market afterwards.

Limitations

FOK orders fail frequently in fast markets. If you consistently receive cancellations, consider IOC orders or adjust size and price tolerance.

Missed Opportunities

Rigid FOK usage can lead to missed trades when partial fills would have been acceptable. Evaluate whether the all-or-nothing condition matches your strategy.

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