Definition
A Fill or Kill (FOK) order requires immediate execution of the entire order quantity at the specified price or better. If the complete order cannot be filled instantly, it is canceled entirely. FOK orders are used when partial fills are unacceptable, often by institutional investors trading large blocks of shares who need certainty about their position size. This order type helps avoid market impact from partial fills becoming public.
Example
A fund manager needs exactly 50,000 shares for a portfolio rebalance. They place a FOK order at $100. If only 45,000 shares are available at that price, the entire order cancels.
FAQ
What is Fill or Kill (FOK)?
An order that must be executed immediately and completely, or canceled entirely.
Why is Fill or Kill (FOK) important?
Fill or Kill (FOK) helps investors evaluate trading mechanics and make more informed decisions.
Related Terms
Immediate or Cancel (IOC)
An order requiring immediate execution with any unfilled portion canceled.
All or None (AON)
An order that must be filled completely or not at all, but without immediate execution requirement.
Market Order
An order to buy or sell a security immediately at the best available price.