What it means
Order book imbalance compares the size of resting limit orders on the bid side with the ask side within a few levels of the current price. A common measure is (bids − asks) / (bids + asks).
It is about orders that have not traded yet, unlike delta, which is about executed trades.
Why traders use it
If much more size is resting on the bid than on the ask, sellers need more effort to push price down. Short-term traders use imbalance as context for direction over the next seconds or minutes.
Chart examples
Heavier bids while price drifts up
How to identify it objectively
- 1Choose a fixed depth (for example 10 levels) and measure bids versus asks.
- 2Positive imbalance: bids heavier; negative: asks heavier.
- 3Look for persistence, not single snapshots.
- 4Compare with what price actually does.
Bullish use
- 1Bids consistently heavier near price.
- 2Price holds or drifts up.
- 3Use it as context for long setups.
Bearish use
- 1Asks consistently heavier near price.
- 2Price holds or drifts down.
- 3Use it as context for short setups.
What confirms it
- Imbalance persists and price agrees.
What invalidates it
- Large orders disappear as price approaches (pulled or spoofed).
How a hypothetical setup is built
Entry
Only with a price-based trigger; imbalance is context.
Stop
From the trigger.
Target
From the trigger.
A hypothetical illustration of how the concept is turned into a plan, not a recommendation. Practise it on a paper account first.
Related concepts
- Order FlowAbsorption
- LiquidityBuy-Side and Sell-Side Liquidity (BSL / SSL)
- Order FlowStacked Imbalances
- Full guide on The TradeskillLiquidity Heatmap Explained
Historical testing
Not tested on The Tradeskill. Order book data is the least stable kind of market data: orders can be added and cancelled in milliseconds.
Limitations: when it fails
- Spoofing: visible orders may never be meant to trade.
- Each exchange has its own book.
- Snapshots change constantly.
Knowledge check
Pick an answer to see the explanation. Nothing is saved.