Fill
A confirmed execution of an order — the trade happened, shares changed hands at a specific price and time.
A fill is the completion of an order. When your order executes, you receive a fill report confirming the quantity traded, the execution price, and the timestamp. Multiple partial fills at different prices can satisfy a single order.
The average fill price is the volume-weighted average of all partial fills, and this is the price that determines your cost basis or exit proceeds.
Tracking fill quality — comparing your fills to VWAP, the NBBO at time of order, and benchmark prices — is how institutions measure execution performance over time.
Related Terms
Execution
The process of completing a trade — from order submission through matching and confirmation. Execution quality affects real-world returns.
BeginnerMarket Order
An order to buy or sell immediately at the best available price. Guarantees execution but not the fill price.
BeginnerOrder Book
The real-time record of all outstanding buy and sell limit orders for an asset, organized by price level.
BeginnerPartial Fill
When only part of an order is executed — common with large orders or low-liquidity conditions.
BeginnerSlippage
The difference between the expected fill price and the actual fill price. Positive slippage benefits you; negative slippage costs you.
Beginner