A fill-or-kill order, often abbreviated FOK, instructs a market to fill the entire requested quantity immediately or cancel the order. It prevents a trader from receiving only a partial position when full execution is required.
The order can reduce partial-fill risk but may fail in a thin or fast-moving market. An automated strategy should handle cancellation explicitly and verify market depth, timing and price limits before attempting another action.
Acronyms and aliases
FOK acronymfill or kill variant
Related terms
Frequently asked questions
What does FOK mean in trading?
FOK means fill or kill, an instruction to execute the whole order immediately or cancel it without a partial fill.
Why would a trading bot use a fill-or-kill order?
It can avoid an unintended partial position when the strategy requires the full quantity at a defined time and acceptable price.
