Fill or Kill (FOK): What It Means for Australian Traders in 2025

In Australia’s fast-evolving share and crypto markets, speed and certainty often make the difference between a successful trade and a missed opportunity. That’s where the Fill or Kill (FOK) order comes into play. If you’ve ever wondered how professional traders lock in deals at lightning speed without leaving anything to chance, this order type is a core part of their toolkit.

What Is a Fill or Kill (FOK) Order?

A Fill or Kill order is a specialised instruction given to a broker or trading platform: either fill the entire order immediately at the specified price or better, or cancel it outright. There’s no partial fulfilment and no waiting in the queue. This approach is especially useful in volatile markets or for large trades where price slippage can quickly erode profits.

• Fill: The full order is executed instantly, at your price or better.

• Kill: If the whole order can’t be filled immediately, it’s cancelled. No part of the trade goes through.

For example, if you place a FOK order to buy 1,000 shares of Commonwealth Bank at $110 per share, the order will only execute if all 1,000 shares can be bought at $110 or less. If not, the order is cancelled—no shares are bought.

Why Use FOK Orders? Real-World Benefits

Australian investors and traders are increasingly using FOK orders to manage risk and maintain control, particularly as the ASX and crypto exchanges have become more sophisticated in 2025. Here’s why FOK orders are gaining traction:

• Certainty in Volatile Markets: With rapid price swings, especially in sectors like lithium mining or digital assets, FOK ensures you don’t end up with only a portion of your intended trade.

• Managing Large Orders: Institutional investors or SMSFs trading large volumes can avoid market impact by ensuring the entire order is filled at a single price.

• Time Efficiency: No need to monitor open orders or deal with partial fills that can complicate portfolio management.

In 2025, with increased algorithmic trading on the ASX and tighter spreads in popular ETFs, FOK orders are a tactical choice for those who can’t afford delays or uncertainty.

FOK in Practice: Platforms, Policy, and Pitfalls

Not every broker or platform supports FOK, and the rules may differ across markets. In 2025, leading Australian brokers like SelfWealth, CommSec, and major crypto exchanges have rolled out advanced order types, including FOK, but always check your provider’s order entry options before relying on them.

Recent policy updates from the ASX in late 2024 have improved transparency around order execution, making it easier to see when and why a FOK order was killed. This move, part of a broader push for market fairness, is designed to help retail investors understand how their orders interact with the order book.

Potential pitfalls include:

• Liquidity Constraints: In illiquid stocks or small-cap shares, FOK orders often get killed—there simply isn’t enough volume at your target price.

• Overuse: Using FOK on every trade may lead to missed opportunities, especially if you’re too aggressive with your price limits.

One recent example: during the 2025 February reporting season, a flurry of FOK sell orders in tech stocks resulted in many trades being cancelled as prices dropped sharply after disappointing earnings. Traders who used FOK avoided partial fills and slippage, but those who set their limits too high missed out on the rebound that followed.

Who Should Consider FOK Orders in 2025?

FOK isn’t just for institutional traders. Active investors, day traders, and anyone looking to execute large trades quickly can benefit, especially when:

• You want all-or-nothing certainty in fast-moving or thinly traded markets.

• You’re trading on news, earnings releases, or other market-moving events.

• Your strategy depends on not leaving residual positions open.

However, for most buy-and-hold investors, market or limit orders will be sufficient.