Price Slippage

Slippage is the difference between the expected price of a trade and the actual average execution price. It happens because a large enough order consumes multiple levels of the order book; the first portion fills at the best price, but subsequent portions fill at progressively worse prices.

A concrete example:

• BTC/USD order book shows: 0.5 BTC bid at $100,000; 1.0 BTC bid at $99,950; 2.0 BTC bid at $99,900; further down...
• You sell 3 BTC as a market order.
• The first 0.5 BTC fills at $100,000.
• The next 1.0 BTC fills at $99,950.
• The next 1.5 BTC fills at $99,900.
• Your average execution: ~$99,933 vs. the "headline" top-of-book of $100,000.
• Slippage: ~$67 per BTC, or about 0.07%.

What drives slippage:

• Order book depth at each price level. Deep books absorb large orders with minimal slippage; thin books slip significantly even on modest size.
• Order size relative to typical volume. A 1 BTC order on Binance or Coinbase is trivially absorbed. A 1,000 BTC market order anywhere will move the market.
• Time of day / liquidity windows. Crypto markets have liquidity cycles; weekend or off-hours trading sees worse slippage.
• Exchange-specific liquidity. Coinbase and Binance offer deep liquidity for BTC/USD and BTC/USDT. Smaller exchanges and exotic pairs have shallower books.

Defenses against slippage:

• Limit orders. Set a maximum acceptable execution price; the order rests on the book and only fills if the market comes to it. Trade execution time for slippage protection.
• TWAP (time-weighted average price) algorithms. Break a large order into smaller pieces executed over hours, getting an average price close to the period's VWAP.
• Iceberg orders. Hide the full order size to avoid signaling intent and triggering front-running.
• OTC desks for large size. Negotiate a single price for the full order, avoiding the public order book entirely.

For ordinary users buying or selling under $10K worth of BTC at a time, slippage is typically negligible (under 0.05%). For larger size, slippage becomes a meaningful cost component. For very large trades (multi-million USD), slippage management is a substantial portion of execution strategy.