The Fill-or-Kill (FOK) Order Strategy is a tactical execution method used by precision-based traders to enter or exit positions instantly at a specified price—or not at all. This strategy is designed for traders who operate in fast-moving, liquid markets where timing, price, and execution certainty are critical.

FOK orders are typically used in high-frequency trading (HFT), institutional strategies, and disciplined scalping approaches. They help avoid partial fills, slippage, or exposure to unwanted market movement.

What Is a Fill-or-Kill (FOK) Order?

A fill-or-Kill order is an instruction to fill the entire order immediately at the specified price or cancel it entirely. If even a small portion of the order cannot be filled at the desired price, the entire order is killed (cancelled).

FOK orders are a subset of advanced order types, typically found on:

• ECN platforms
• Direct Market Access (DMA) brokers
• Algorithmic trading engines

Why Use the FOK Strategy?

• Avoid partial fills in fast-moving markets
• Maintain full control over price execution
• Ensure clean entry and exit during scalping or news trading
• Minimise slippage and risk exposure

This is especially useful when entering or exiting with large volume near key levels or in volatile markets where price can shift within milliseconds.

Ideal Use Cases for FOK Orders

• Scalping strategies at breakout or rejection zones
• Liquidity-sensitive trades, such as around news releases
• Institutional entry points where full size must be guaranteed
• Stop runs or front-running tactics with minimal risk exposure

Step-by-Step: How the Strategy Works

Step 1: Identify the Execution Zone

Use your trading strategy (Ichimoku, VWAP, S&R, price action) to locate a price level where:

• You want to enter a position at a specific price
• You must be fully filled or prefer not to enter at all

Step 2: Monitor Market Depth (Level II)

Ensure there’s sufficient volume and liquidity at your desired price:

• Confirm with the order book (DOM)
• Look for clusters of passive liquidity at your target level

Step 3: Submit FOK Order

Example:

• You want to buy 10 lots of EUR/USD at 1.0850
• Submit a FOK Buy Limit Order at 1.0850 for 10 lots

Outcome:

• If the full 10 lots are available → order is filled instantly
• If only 7 lots are available → entire order is cancelled
• If no match is available → cancelled without delay

Step 4: Retry or Reassess

If your order is killed:

• Do not chase price
• Wait for price to return and re-queue another FOK order
• Alternatively, consider pegged limit or IOC (Immediate-or-Cancel) if partial fills are acceptable

Example: USD/JPY FOK Order in News Volatility

• NFP results are due, volatility is expected
• Price spikes down to your key level of 148.50
• You place a Buy FOK order for 5 lots at 148.50
• Full fill occurs instantly—trade is executed with zero slippage
• Price bounces to 149.10 within 2 minutes
• Exit manually or with TP bracket

Benefits of the Fill-or-Kill Strategy

• Guaranteed price control
• Zero tolerance for slippage or partial fills
• Suitable for algorithmic and scalping strategies
• Reduces overexposure during volatility
• Efficient for high-volume entries without needing to split orders

Drawbacks to Be Aware Of

• No flexibility—if full size isn’t available, order fails
• Requires deep liquidity—not ideal in thin or exotic markets
• Not supported on all platforms—must use DMA or ECN brokers
• Manual re-entry required—not ideal for slow decision-makers

Platform & Broker Requirements

To use FOK orders effectively, your broker must support:

• Fill-or-Kill (FOK) order types
• Real-time Level II data and market depth
• Fast execution infrastructure (low latency)
• Preferably an ECN environment

Who Should Use This Strategy

• Scalpers using breakout or limit reversion models
• Institutional-style traders focused on price integrity
• High-frequency traders or algo developers
• Manual traders operating in news-sensitive zones

Conclusion

The Fill-or-Kill Order Strategy is a laser-focused execution model for traders who demand speed, size, and certainty. It eliminates slippage, avoids exposure to unfavourable fills, and provides full control over trade execution—making it an elite-level tool for scalping, news trading, and institutional-style positioning.

To learn how to build advanced execution tactics like FOK into your professional strategy, enrol in our Trading Courses and take your market timing and risk control to the next level.