In a Dark Pool, How Does the Execution of a Limit Order Differ from a Public Exchange?

A dark pool is a private exchange where trading occurs without the pre-trade transparency of a public order book. In a dark pool, a limit order is matched against other hidden orders at the mid-price of the public exchange's BBO.

This prevents the large order from revealing its size and causing price impact (slippage) on the public market. Execution is typically slower and less certain than on a public exchange, but it offers significant slippage control for large block trades.