Top of market order
Family II · Orders
Not to be confused with double top.
Top of market order is a marketable instruction that executes against the best displayed price on the opposite side of the book. It is not a separate order type on most venues; it is a market order or an aggressively priced limit order that crosses the spread. The term describes the intent to trade at the top of the book rather than to queue passively.
Execution and price
A top of market order fills against the highest bid or lowest offer currently displayed. If the size at that price is smaller than the order, the remainder continues to the next price level, so the average fill price can be worse than the quoted top of book. Slippage is therefore a normal outcome when depth is thin.
On many exchanges a market order is converted internally into a marketable limit order with a protective collar, and the collar rules vary by venue and asset class. A top of market order is best understood as the behaviour, not a distinct order flag.
Worked example
Practical notes
- Size relative to displayed depth determines whether the order stays at the top of book or walks the ladder.
- Latency matters: the top of book can change between order entry and matching.
- Some venues reject or reprice market orders that would exceed a price band; the exact band varies by market and instrument.
Often confused with
- double top
- A double top is a chart pattern of two failed highs in a price series, not an order instruction; the visible sign is that it appears on a price chart, whereas a top of market order appears in an order ticket or trade log.