Also called book imbalance
Order imbalance
The share of the displayed size sitting on the bid versus the ask. Bid heavy says buyers are queued; ask heavy says sellers are. A lean, not a forecast, and it changes every second.
Updated 2026-09-16
Imbalance compares the size resting on the bid with the size resting on the ask at the inside. Four thousand bid against one thousand offered is 80 percent bid heavy: more people queued to buy at the best price than to sell at it. The desk draws it as a bar and names the lean.
It is a short-horizon read and it is easy to fake. Displayed size can be pulled, layered, or hidden behind iceberg orders that show a fraction of their real size, so a heavy bid is a statement about the next few seconds, not the next hour. The honest use is as context for a limit price: with the book bid heavy, a resting bid is more likely to be in a queue than to fill.
See also
- Top of book — The best bid and best ask and the size resting at each. It is what a market order trades against, and on one venue it is a sample of the whole market, not the whole market.
- Order book — The list of resting buy and sell orders at each price. The inside of it is the bid and the ask; the rest is depth, which the free IEX feed does not publish.
- Liquidity — How easily something can be sold near its quoted price. A liquid stock absorbs your order; an illiquid one moves against you as you fill it.
Educational content, not investment advice. Angie explains how a valuation is built so you can judge it yourself. What you do with that is your call.
