The difference between the expected price and the actual execution price, usually caused by thin liquidity or large order sizes.
Slippage occurs when your order executes at a different price than expected. In prediction markets, this typically happens when you place a market order that's larger than the available liquidity at the best price.
For example, if the best Yes price is $0.55 with 200 contracts available, but you want 500 contracts, the last 300 will fill at progressively worse prices. Your average fill might be $0.57 — $0.02 of slippage.
Slippage is an invisible cost on top of stated fees. It's most impactful on platforms with thin order books. Use limit orders to control slippage.