Market Order

A market order fills immediately at the best available price. Speed comes first. Price is whatever the book or pool offers. Execution is likely if any liquidity exists. There is no price guarantee. In tight markets you fill near the quote. In thin markets you walk the book. A large buy might fill at $100, $101, $102 as it eats asks. Impact grows with size versus depth.

Professionals usually avoid market orders for large size. They use limits or algo execution. On DEXs, swaps against AMM pools behave like market orders, with a slippage cap as a backstop. MEV makes on-chain market orders extra risky. Bots see the pending swap and sandwich it, buying before and selling after. Private mempools and MEV-protection relays reduce that.

In liquid markets with tight spreads, market orders execute close to displayed prices. Professional traders typically avoid market orders for size, using limit orders or algorithmic execution to minimize impact. A market order executes immediately at the best available price, prioritizing speed of execution over price certainty. You get the trade done now, accepting whatever the market offers.

Market orders guarantee execution (assuming any liquidity exists) but provide no price guarantee, the actual execution price depends on current order book depth or AMM pricing. A market order says fill now. In thin books the fill can be far from the last print.