Order Flow Explained: Delta, Absorption and Imbalances

A limit order is passive: it sits in the book and waits. A market order is aggressive: it takes whatever is available. Markets only move when aggressors exhaust passive size at a price. That means a level breaks not because it is "weak" but because the resting orders defending it were fully consumed or pulled.

This is the mental model to keep: at any FTS published level, the question is never "will it hold?" It is "is passive size absorbing the aggression, or is the aggression eating through it?"

Delta is buy market volume minus sell market volume over a period. Positive delta means buyers were more aggressive. It does not guarantee price went up — and that mismatch is the most useful signal in order flow. Strong positive delta with almost no upward price progress means someone large is selling passively into every buy. That is absorption.

Cumulative delta strings those readings together across the session. When cumulative delta makes a higher high while price makes a lower high, aggressive buyers are working harder for less. That divergence, sitting on an A+ Resistance level, is a much higher-quality short than the level alone.

Absorption looks like a stalled price with heavy volume: the tape prints thousands of contracts and price moves two ticks. It signals a large passive participant, and it usually resolves against the aggressors. Exhaustion is the opposite tell — a violent push with rapidly shrinking volume on each new tick. Aggressors are still trying, but nobody is left to join them.

Practical rule: absorption at support is a long clue, absorption at resistance is a short clue. Exhaustion is a continuation-failure clue: the move is out of fuel, not necessarily reversing yet.

An iceberg order displays a small quantity but keeps refilling as it is hit. On the tape it looks impossible: the book shows 40 contracts offered, 900 trade there, and the offer is still 40. Icebergs mark levels an institution genuinely wants to defend. When an iceberg finally lifts or gets consumed, the move that follows is often fast because the anchor is gone.

A diagonal imbalance compares the bid volume at one price with the ask volume one tick above, typically flagged at a 3:1 ratio or greater. One imbalance is noise. Three or more stacked consecutively is a footprint of a directional participant pushing through a zone, and those stacks often act as support or resistance on the retest.

Order flow is a timing tool, not a location tool. It answers "now?" but is unreliable at answering "where?" That is what the published package is for. The workflow that works: wait for price to reach a published A+ level, then require an order flow confirmation — absorption, a delta divergence, or a failed auction with stacked imbalances against the move — before you commit risk.

When there is no confirmation at the level, there is no trade. Missing a move costs nothing; entering without evidence costs real money.