# All or None Orders

> An all or none order must fill completely or not at all, but can wait to do so. Learn how AON orders work, why they often fill later and when they make sense.

Source: https://learn.tradelabsai.com/orders/all-or-none-orders/  
Track: Orders and Execution · Level: Intermediate · Updated: 2026-10-03  
Publisher: TradeLabs AI (https://tradelabsai.com). Education, not financial advice.  
Cite as: TradeLabs Learn, "All or None Orders", https://learn.tradelabsai.com/orders/all-or-none-orders/

An all or none (AON) order is an instruction to fill the entire order in one go or not at all. Unlike a fill or kill order, it does not have to happen immediately: an AON order can wait, for the day or longer, until enough size is available at your price to complete it in full. It protects you from partial fills, at the cost of often waiting longer or missing the trade altogether.

## How an AON order works

**Example: An AON buy order**
You want 2,000 shares of a small company at $8.50 or less, and you do not want a partial position. You place an AON buy limit at $8.50.
Over the morning, sellers offer 400, then 600, then 300 shares at $8.50. A normal limit order would have filled 1,300 shares. Your AON order fills nothing, because no single opportunity could complete all 2,000.
In the afternoon, a seller offers 2,500 shares at $8.48. Your AON order fills all 2,000 at $8.48.

## AON compared with similar instructions

| | All or none | Fill or kill | Normal limit |
|---|---|---|---|
| Full fill required | Yes | Yes | No |
| Must fill immediately | No | Yes | No |
| Can rest and wait | Yes | No | Yes |
| Partial fills | Never | Never | Allowed |

See [IOC and FOK Orders](https://learn.tradelabsai.com/orders/ioc-and-fok-orders/) for the immediate versions.

## Why someone would use AON

- **Avoiding small, costly partial fills.** If your broker charges a commission per fill or per day, many small partial fills of the same order can add costs.
- **Positions that only make sense at full size.** For example, buying exactly enough shares to cover an options position or to complete a planned hedge.
- **Odd lot issues.** In some markets, a leftover small piece of a position can be awkward or expensive to trade later.

## The drawbacks

1. **Lower priority.** Because an AON order cannot accept a partial fill, it is often passed over by the market. Other orders at the same price can fill ahead of yours.
2. **Missed trades.** Your price can trade all day in small pieces without your order ever completing.
3. **Limited availability.** Many venues and brokers no longer support AON for stocks, or only for certain order types. Some exchanges handle it differently from others.
4. **Not useful for liquid markets.** In heavily traded stocks, partial fills are rare for normal size orders anyway, so AON adds little.

**Watch out: AON is not a substitute for liquidity**
If you need AON because the market cannot absorb your size, the market may be too thin for that size. Consider trading smaller or splitting the order over time instead.

## Alternatives to AON

- **Normal limit orders,** accepting partial fills and adjusting your stops and size accordingly.
- **Minimum quantity instructions,** offered on some platforms, which require a minimum fill size per execution rather than all of it.
- **Iceberg orders** that show only part of a large order. See [Hidden and Iceberg Orders](https://learn.tradelabsai.com/orders/hidden-and-iceberg-orders/).
- **Algorithmic execution** that works a large order over time. See [VWAP, TWAP and POV Execution](https://learn.tradelabsai.com/orders/vwap-twap-and-pov-execution/).

## AON in other contexts

The term also appears in securities offerings, where an underwriter agrees to sell an entire issue or cancel it. And in options trading, some brokers allow AON on multi leg orders so that all legs fill together. Most modern platforms fill multi leg spreads as a single package automatically.

## Frequently asked questions

### What does all or none mean in trading?

It means the order must be filled in full in a single execution, or not at all. It can stay open and wait for enough size at your price.

### Why is my all or none order not filling?

Because no single seller or buyer has offered enough size at your price, or other orders have priority. AON orders often fill less frequently than normal orders.

### Is AON the same as fill or kill?

No. Fill or kill must fill completely and immediately. AON must fill completely but can wait.

## Sources

- Wikipedia, [All or none](https://en.wikipedia.org/wiki/All_or_none)

## Continue learning

- Next lesson: [Opening and Closing Orders: MOO, MOC, LOO, LOC](https://learn.tradelabsai.com/orders/opening-and-closing-orders/)
- Previous lesson: [IOC and FOK Orders](https://learn.tradelabsai.com/orders/ioc-and-fok-orders/)
- Related: [IOC and FOK Orders](https://learn.tradelabsai.com/orders/ioc-and-fok-orders/): Immediate or cancel and fill or kill orders must trade at once or be cancelled. Learn how they differ, when traders use them and how partial fills are handled.
- Related: [Time in Force: Day, GTC and GTD Orders](https://learn.tradelabsai.com/orders/time-in-force/): Time in force sets how long an order stays active. Learn day orders, good till cancelled, good till date and extended hours settings, with examples and pitfalls.
- Related: [Limit Orders](https://learn.tradelabsai.com/orders/limit-orders/): A limit order trades only at your price or better. Learn how buy and sell limits work, why they may not fill, queue priority and how to set a smart limit price.
- Related: [Fill Probability and Queue Position](https://learn.tradelabsai.com/orders/queue-position/): Your place in the order queue decides whether a limit order fills. Learn how queues work, how to estimate fill probability and why fills can be a warning sign.
- Related: [Hidden and Iceberg Orders](https://learn.tradelabsai.com/orders/hidden-and-iceberg-orders/): Iceberg orders show only part of a large order; hidden orders show none of it. Learn how they work, their priority trade off and how to spot icebergs in the book.