How to judge liquidity quickly
You do not need a data terminal. Three visible signals tell you most of what matters before you place an order.
- Spread — tight spreads are the clearest sign of competition among market makers
- Volume — sustained daily turnover, not a single spike
- Depth — how much size rests within a small distance of the mid
Liquidity is not constant
The same instrument can be deeply liquid at 14:00 London and almost untradeable at 03:00. Liquidity follows the sessions where its natural participants are awake, and it evaporates in exactly the conditions where you most want to exit.
A mid-cap token trading $40m a day looks fine — until a sell-off hits, market makers withdraw, and a $50k order moves it 6%. Volume measured in calm conditions does not survive the stress test.
Why it matters more than most beginners think
Illiquidity does not appear on your statement as a line item. It shows up as worse fills, wider stops, and positions you cannot exit at the price you had in mind. On thin instruments it is often larger than every explicit fee combined.
Trading illiquid markets responsibly
- Use limit orders almost exclusively
- Cut position size — assume the exit is worse than the entry
- Avoid stops placed just beyond obvious levels in thin books
- Scale in and out rather than trading in one clip