The two families of columns
Every DOM column belongs to one of two families, and confusing them is the most common beginner mistake:
- Depth columns show resting limit orders — what market participants say they intend to do. Intent can be pulled, spoofed, or replenished in milliseconds.
- Volume columns show executed trades — what actually happened. History can't be faked.
Order-flow reading, at its core, is comparing the two: where does stated intent sit, and does executed volume confirm or contradict it?
Depth: the Bid and Ask columns
The Bid column shows the number of contracts resting to buy at each price below the market; the Ask column shows contracts offered for sale above. Large resting size can act as a magnet (algos work toward liquidity) or a wall (price struggles to trade through it) — but because it's only intent, experienced traders treat big size with suspicion until volume confirms someone is actually trading against it.
Volume at price
The Volume column accumulates contracts traded at each price during the session, often with heat coloring so high-traffic prices stand out. It answers: where has business been done today? Prices with heavy traded volume tend to act as reference levels — the market has agreed to transact there once and often respects the area on a revisit. (This is the ladder-view cousin of a Volume Profile.)
Delta: the aggression column
Per-price delta splits traded volume by who initiated it. A trade that executes at the ask is buyer-initiated (someone paid up); a trade at the bid is seller-initiated (someone hit the bid). Delta = buyer-initiated minus seller-initiated volume:
- Positive delta at a price — buyers were aggressive there (lifting offers).
- Negative delta — sellers were aggressive (hitting bids).
The interesting reads are the divergences: heavy positive delta at a high that fails to break (buyers absorbed — trapped longs), or persistent negative delta at a low that won't go lower (sellers absorbed — a floor being built).
Cumulative delta
Cumulative delta (often shown as a strip above the ladder or a chart pane) sums per-price delta across the session: a running scoreboard of which side has been in control since the open. Two practical notes:
- Reset time matters. Futures tools commonly reset at the Globex session open (5:00 PM CT). A delta line that resets at midnight tells a different story than one anchored to the session.
- Classification methodology matters. Live bid/ask comparison, the tick rule, and platform-classified volumetric data each produce slightly different numbers — which is why two tools rarely agree exactly. Consistency within one tool is what makes the read usable.
Position-context columns
Execution-focused DOMs often add columns that only exist while you're in a trade: estimated P&L at each price for your current size, and distance from your average entry in ticks or points. These aren't order-flow signals — they're risk instrumentation, useful because they eliminate mental arithmetic exactly when you're least equipped to do it.