Partial Fill
When only part of your order executes and the rest stays open or is canceled.
Also called: partially filled
In plain language
Partial fills happen when there is not enough size available at your price. You get what was there; the remainder waits, or is canceled depending on the order’s time in force.
This leaves you with a smaller position than planned, which quietly changes your risk. Half the intended size means half the intended risk — and half the intended reward.
They are common in illiquid instruments, in large orders, and with immediate-or-cancel instructions.
Why it matters
A partially filled entry paired with a full-size stop calculation means your position no longer matches your plan in either direction.
Common mistakes
- Assuming the whole order filled and managing the trade at the wrong size.
- Chasing the unfilled remainder at a worse price, ruining the average entry.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
The actual execution of an order, at the price and quantity you really received.
How easily an asset can be bought or sold without moving its price.
The instruction that says how long an order stays active before it expires.
An order to buy or sell at a specified price or better — it may not fill at all.
The amount of an asset you buy or sell in a single trade.