What Is Slippage? Price Impact in Prediction Market Trades
Slippage is the gap between an expected price and the average execution price when an order crosses limited order-book depth.
Definition
Slippage is the difference between the price you expect to pay for a trade and the price you actually receive. It typically occurs when you place a market order that consumes multiple price levels in the order book.
Example
The order book for YES shares shows:
- 100 shares available at $0.65
- 200 shares available at $0.66
- 500 shares available at $0.68
If you market-buy 350 shares, you will get:
- 100 shares at $0.65
- 200 shares at $0.66
- 50 shares at $0.68
Your average price is $0.661 instead of the displayed $0.65. That $0.011 difference is slippage.
How to Minimize Slippage
- Use limit orders — set the maximum price you are willing to pay. Your order will only fill at or below that price.
- Trade smaller sizes — break large orders into smaller pieces.
- Choose liquid markets — markets with deeper order books have less slippage.
- Trade on CLOB platforms — order book exchanges like Purrdict generally have better execution than AMM-based alternatives.
Slippage on Purrdict
Purrdict benefits from Hyperliquid’s high-performance matching engine, which processes thousands of orders per second. Combined with professional market maker participation, this results in deep books and minimal slippage for most trade sizes.