Fill or Kill

Action

Fill or Kill (FOK) represents a specific order type utilized across cryptocurrency exchanges, options markets, and financial derivatives platforms, mandating immediate and complete execution of a trade at the specified price or cancellation of the order. This instruction prioritizes price certainty over guaranteed execution, functioning as a conditional directive for brokers or exchange matching engines. Its application is prevalent among institutional traders and algorithmic systems where partial fills introduce unacceptable risk or operational inefficiencies, particularly in volatile asset classes. The FOK order type inherently limits market impact, as large orders are either fully absorbed or remain unexecuted, preventing price slippage.