All-or-None (AON) Order
The Formal Definition
A conditional limit order that requires the entire specified quantity of shares or contracts to be filled in its entirety or not at all, explicitly prohibiting partial fills while remaining active until canceled or expired.
Execution Rule: Fill Quantity = Total Specified Order Size OR Fill Quantity = 0 (Partial Fills Prohibited)
Cole Barrett's Reality Check
The Unvarnished Bottom Line"AON orders stop brokers from breaking a 2,000-share buy into ten tiny fills that each rack up ticket fees. But there is a hidden cost: an AON order sits on the sidelines if a seller shows up with 1,900 shares at your price. You give up execution priority to guarantee batch size."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: Placing an order to purchase 5,000 shares of an illiquid small-cap stock at a strict $12.00 limit price
| Execution Metric | All-or-None (AON) Limit Order | Standard Unrestricted Limit Order |
|---|---|---|
| Fee / Rate | Single ticket fee | Pro-rated per-share pricing |
| Spread / Buffer | Sellers offered 2,500 shares at $12.00, then price rallied to $12.80 | Absorbed the 2,500 shares at $12.00; remaining 2,500 unfilled |
| Execution / Status | Zero shares filled because matching block of 5,000 was unavailable | Partial fill secured on 50% of the trade size |
| Total Cost / Result | Suffered opportunity drag due to all-or-nothing restriction | Participated in the rally despite thin resting book depth |
How Brokers Weaponize This Term
Brokerages charging per-ticket minimum commissions steer clients away from AON orders, benefiting when block orders fragment into multiple executions that trigger recurring base ticket fees.
Broker Evaluation Matrix
Cole Approves
Charles Schwab / Fidelity: Native support for AON, FOK, and complex special condition instructions on lit exchange routes.
Read Audit →Cole Flags / Avoids
Simplified Neobrokers: Eliminates special conditions like AON, forcing fragmented fills on larger retail orders.
View Trap Details →Frequently Asked Questions
How does an AON order differ from a Fill-or-Kill (FOK) order?
An AON order stays open until it can be filled entirely; an FOK order must fill entirely immediately upon arrival at the market, or it cancels instantly.
Do AON orders hold priority on public exchange order books?
No. Because they cannot execute against partial resting liquidity, exchanges treat AON orders as non-displayed or low-priority compared to standard limit orders.