Fill or kill (FOK) orders: meaning and how they work
Some traders want all of their order done right away, or nothing at all. A fill or kill order does exactly that. This page explains what a fill or kill order is, how it works, how it differs from IOC and whether it is available in India.
Quick answer
A fill or kill (FOK) order is an instruction to buy or sell a set quantity immediately and in full at the stated price or better. If the whole quantity cannot be filled at once, the entire order is cancelled. There is no partial fill and no waiting. FOK is common on some global markets, but on Indian exchanges the standard immediate option for regular orders is IOC.
Key takeaways
- A fill or kill order must fill completely and at once.
- If it cannot, the whole order is cancelled.
- It allows no partial fills.
- IOC allows partial fills, FOK does not.
- Indian exchanges offer Day and IOC validity for regular orders.
What is a fill or kill order?
It combines two conditions. First, the order must be executed immediately. Second, it must be executed in full. If either condition cannot be met, the order is 'killed', meaning cancelled at once.
For example, a trader places an FOK order to buy 5,000 shares at Rs 200 or lower. If at that moment there are at least 5,000 shares on offer at Rs 200 or below, the order fills completely. If only 3,000 are available, nothing is bought and the order is cancelled.
Why do traders use FOK orders?
Some strategies only work if the full quantity is traded together. For example, an arbitrage trade may need a set number of shares at a set price. A partial fill could leave the trader with an unhedged position.
FOK also prevents an order from sitting in the order book and showing the trader's interest to the market. Either the trade happens right away, or the trader moves on.
How is FOK different from other order types?
| Order type | Must fill at once? | Partial fill allowed? |
|---|---|---|
| Fill or kill (FOK) | Yes | No |
| Immediate or cancel (IOC) | Yes | Yes |
| All or none (AON) | No, can wait | No |
| Day order | No, valid for the day | Yes |
The closest relative is the immediate or cancel order, which also must act at once but allows a partial fill, cancelling only the unfilled part. All or none also needs the full quantity, but it can wait in the market instead of cancelling at once.
Is fill or kill available in India?
On NSE and BSE, regular orders in the cash and F&O segments can usually be placed with Day validity or IOC validity. A separate FOK option is not part of the standard order validity choices offered to most investors. Traders who want immediate execution typically use IOC.
Some global exchanges and currency trading platforms do offer FOK. Rules differ by venue, so it is important to check what your broker and exchange support before choosing an order type.
The key point to remember
A fill or kill order is all or nothing, right now. It suits strategies that need the full quantity at once, but in fast or thin markets it may often be cancelled without any trade.
Frequently Asked Questions
What is a fill or kill order?
A fill or kill order must be executed immediately and in full at the stated price or better. If it cannot, the whole order is cancelled.
What is the difference between FOK and IOC?
Both must act at once. IOC allows a partial fill and cancels the rest, while FOK allows no partial fill and cancels the entire order.
Is FOK the same as all or none?
No. Both need the full quantity, but an all or none order can wait in the market, while FOK must fill at once or be cancelled.
Can I place an FOK order on NSE?
Regular orders on NSE and BSE usually use Day or IOC validity. A separate FOK option is not part of the standard choices for most investors.
When is an FOK order useful?
It is useful for strategies that need the full quantity at once, such as some arbitrage trades, where a partial fill could create unwanted risk.
Disclaimer: Investments in the securities market are subject to market risks. Please read all related documents carefully before investing. This article is intended for informational and knowledge purposes only and should not be considered tax, financial, or investment advice. Tax laws and deductions may vary based on individual circumstances and regulatory changes. Readers are advised to consult a qualified tax advisor or financial professional before making any investment or tax planning decisions.
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