Market Order

A market order is an order to buy or sell immediately at the best available price. It does not specify a price; it specifies a quantity and accepts whatever fills are available in the order book. Market orders are the fastest order type and they trade execution certainty for price uncertainty: you are guaranteed to fill, but the price you fill at can differ from the last quoted price by the slippage of the move.

Why market orders exist

Market orders exist for situations where speed matters more than price improvement. Closing a position during a fast adverse move, executing a stop-out, taking a fill on a setup before it gets away: these all favor market orders. The cost is the bid-ask spread plus any slippage from the move during execution. Most traders pay this cost willingly on exits and avoid it on entries by using limit orders.

How market orders work on Hex37

When you place a market order, the execution engine immediately walks the order book from the best available price upward (for buys) or downward (for sells), filling against resting limit orders in price-time priority until the order quantity is exhausted. On a deep, liquid book, the entire order fills within a few price levels of the top. On a thinner book, the order can sweep multiple levels, and the average fill price diverges further from the inside price. Hex37 applies a slippage model of 0.05% to 0.2% on top of the book-walk to reflect the real-time race conditions on a live exchange.

Market orders and slippage

The slippage on a market order is the difference between the price you saw on the chart at the moment of the click and the average price you actually filled at. On BTC during quiet conditions, slippage on a small market order is often a fraction of a basis point. On thinner alts during fast moves, slippage on a 5x or 10x-notional position can be 0.2% or more. The slippage model on Hex37 surfaces this cost directly: every fill receipt shows the difference between the intended price and the executed price.

Common market-order mistakes

• Using market orders for entries when there is no rush. The spread plus slippage on a market entry is a real cost; over a hundred trades it compounds.
• Sizing market orders without considering book depth. A large market order on a thin book pays much worse slippage than the same order on BTC. Break large orders into chunks or use limit orders if speed allows.
• Forgetting that market orders execute against current book depth. If the book is unusually thin (during a fast move, or on a low-volume asset), your market order pays more than usual.
• Confusing market with limit at the same intended price. A market order will fill at whatever the next available price is. A limit at the same price might not fill at all if the book has moved.