One order, three fills, three prices
Posted: Sat Oct 31, 2026 9:32 pm
One order, three fills, three prices
A 5 lot market buy on a quiet cross. The platform shows a single position. The history tab tells the real story: 2 lots at the quoted price, 2 lots one pip higher, 1 lot two pips higher.
The average entry looks only slightly off. The last fill is the one that really hurt, because it landed at a price the setup never wanted.
Partial fills only happen on true ECN or STP style accounts where the order walks the book. On a market maker account the broker simply fills the whole thing at one price, which feels cleaner but is not always better.
Splitting the order into smaller clips avoids the worst of it. It also multiplies commission when charged per ticket, so the saving has a cost.
Position window shows one line. History shows the truth. Checking history after every larger order is the habit that catches this early.
A worked example: the quoted ask is 1.0850 and a 5 lot buy walks the book. Two lots fill at 1.0850, two at 1.0851, one at 1.0852. The average is 1.08508, only eight tenths of a pip off the quote, so the trade looks fine at first glance. But the last lot sits two full pips above where it was supposed to start, and if the setup only had a three pip target, that lot begins with most of its reward already gone.
At what size does a pair start walking the book on your account?
A 5 lot market buy on a quiet cross. The platform shows a single position. The history tab tells the real story: 2 lots at the quoted price, 2 lots one pip higher, 1 lot two pips higher.
The average entry looks only slightly off. The last fill is the one that really hurt, because it landed at a price the setup never wanted.
Partial fills only happen on true ECN or STP style accounts where the order walks the book. On a market maker account the broker simply fills the whole thing at one price, which feels cleaner but is not always better.
Splitting the order into smaller clips avoids the worst of it. It also multiplies commission when charged per ticket, so the saving has a cost.
Position window shows one line. History shows the truth. Checking history after every larger order is the habit that catches this early.
A worked example: the quoted ask is 1.0850 and a 5 lot buy walks the book. Two lots fill at 1.0850, two at 1.0851, one at 1.0852. The average is 1.08508, only eight tenths of a pip off the quote, so the trade looks fine at first glance. But the last lot sits two full pips above where it was supposed to start, and if the setup only had a three pip target, that lot begins with most of its reward already gone.
At what size does a pair start walking the book on your account?