Market liquidity refers to the ability to absorb buy and sell orders without significantly moving price. It's one of the most important — and often overlooked — factors in trading.
Liquidity metrics:
- Daily volume: number of units traded per day
- Bid/ask spread: tighter spread = more liquid market
- Order book depth: volume available at different price levels
- Average slippage: gap between requested and executed price
Liquidity hierarchy (most to least liquid):
- EUR/USD: $7.5T/day total Forex volume, ultra-liquid pair
- S&P 500 (SPY ETF): $30B+/day
- Bitcoin: $30-50B/day
- Gold (XAU/USD): $200B+/day
- Blue-chip stocks (Apple, Microsoft): $5-15B/day
- Small-caps: $100K-$10M/day, low liquidity
- Exotic altcoins, penny stocks: illiquid, beware
Why it matters for you:
- Illiquid market = wide spreads (sometimes 5% of price) that eat profits
- Not enough counterparties → you might not be able to exit at desired price
- Easy manipulation: a large order radically shifts price → prime "pump and dump" targets
- Liquidity fluctuates: best during London + New York hours, low Asian night, very low crypto weekends
Pro rule: never trade more than 1% of an asset's average daily volume. Beyond that, your own order distorts price.