Market Buy

A market buy is an order that tells an exchange to purchase a coin immediately at whatever price the current sellers are asking, rather than waiting for a specific target price. Instead of naming a price, the trader only specifies the amount to buy, and the exchange's matching engine fills it against the cheapest available sell orders sitting in the order book.

Because a market buy takes liquidity out of the book rather than adding to it, it is classed as a "taker" order and usually carries a higher fee than a resting limit order, which is treated as a "maker" order on most exchanges. Speed and certainty of execution are the trade-off: the order fills almost instantly, but the final price is not guaranteed in advance.

This becomes especially relevant when liquidity is thin. If the order size exceeds what is available at the best ask, the remainder fills at progressively higher prices, a phenomenon known as slippage. On a low-volume altcoin, a large market buy can push the average execution price noticeably above the price shown on-screen moments earlier. On a deep market like Bitcoin, the same order size might fill with almost no price impact.

Traders typically favor market buys when speed matters more than price precision, such as entering a fast-moving trade or reacting to breaking news. For larger orders or illiquid pairs, checking order book depth first, or splitting the trade into smaller pieces, helps avoid paying an unexpectedly high average price.