Price improvement on limit orders: when the fill is better than the order
Posted: Sat Oct 31, 2026 6:07 am
A buy limit at 1.0850 should fill at 1.0850 or lower. Some brokers fill at exactly the limit, even when the market gaps below it. Others pass on the better price.
If the ask jumps from 1.0852 to 1.0846, a limit order at 1.0850 can be executed at 1.0846, which is better than requested. Whether this happens depends on the broker's execution model.
Under a strict model, the order fills at the limit price regardless, and the broker keeps the difference. Under a price improvement model, the client receives the better price. The difference is small per trade, but for someone placing hundreds of limit orders, it accumulates.
The platform's trade history can reveal it. For limit orders, compare the open price to the specified order price. If fills sometimes show a better price, improvement is passed on. If they always match exactly, even after obvious gaps, it isn't.
It can also work against the client in the reverse direction: a stop order that triggers and fills at a worse price is called slippage, and brokers that offer price improvement on limits usually allow negative slippage on stops. That is symmetric in theory but may not be in practice.
A good question to ask support, with a request for a written answer, is how limit orders are filled when the market gaps through the level.
Do the fills on limit orders show any improvement over the requested prices?
If the ask jumps from 1.0852 to 1.0846, a limit order at 1.0850 can be executed at 1.0846, which is better than requested. Whether this happens depends on the broker's execution model.
Under a strict model, the order fills at the limit price regardless, and the broker keeps the difference. Under a price improvement model, the client receives the better price. The difference is small per trade, but for someone placing hundreds of limit orders, it accumulates.
The platform's trade history can reveal it. For limit orders, compare the open price to the specified order price. If fills sometimes show a better price, improvement is passed on. If they always match exactly, even after obvious gaps, it isn't.
It can also work against the client in the reverse direction: a stop order that triggers and fills at a worse price is called slippage, and brokers that offer price improvement on limits usually allow negative slippage on stops. That is symmetric in theory but may not be in practice.
A good question to ask support, with a request for a written answer, is how limit orders are filled when the market gaps through the level.
Do the fills on limit orders show any improvement over the requested prices?