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Key Takeaways
- A bid-ask footprint shows executed volume at each price inside a chart bar.
- The bid column contains seller-initiated volume; the ask column contains buyer-initiated volume.
- Trade delta equals ask volume minus bid volume.
- Read price progress alongside delta to compare aggressive execution with its result.
- The worked bar contains 11,300 contracts and a positive delta of 1,500.
What is a footprint chart?
A footprint chart is a price chart that expands each bar into a grid of volume at price. A bid-ask footprint places seller-initiated volume in the bid column and buyer-initiated volume in the ask column. It shows where trades concentrated and which side initiated them.
A delta footprint displays ask volume minus bid volume. A volume footprint displays their combined total. The delta view shows which side pressed, and the volume view shows where size traded.
Formula
Bar delta = ask-side (buy aggressor) volume − bid-side (sell aggressor) volume, summed across every price level in the bar- Ask-side volume counts contracts or shares that traded at or above the prevailing ask, treated as buyer-initiated.
- Bid-side volume counts contracts or shares that traded at or below the prevailing bid, treated as seller-initiated.
- Positive delta means buyers aggressed more than sellers over the bar; negative delta means the reverse.
Footprint chart example: reading one bar
One five-minute E-mini S&P 500 futures bar prints across six price levels. At 5006.00, 2,100 contracts trade on the ask and 1,000 trade on the bid. Across the whole bar, ask-side volume totals 6,400 contracts and bid-side volume totals 4,900 contracts.
- Price-level delta at 5006.00: 2,100 ask − 1,000 bid = +1,100
- Bar delta: 6,400 ask − 4,900 bid = +1,500
- Total bar volume: 6,400 + 4,900 = 11,300 contracts
The 5006.00 row contains 3,100 contracts and +1,100 delta. Across all six rows, 6,400 ask contracts minus 4,900 bid contracts produces +1,500 delta. Compare that buying pressure with the bar’s price movement.
At 5006.00, 1,000 bid contracts and 2,100 ask contracts produce 3,100 total volume and +1,100 delta. That is the bar’s highest-volume row and its largest delta, so it is where aggressive buying concentrated.
How to read footprint delta and imbalances
Read the price movement alongside the volume split. Large positive delta measures aggressive buying. Compare how far price advances, where it pauses and how much volume trades at the pause. This puts the execution pressure and the market’s response in the same view.
Cumulative delta adds successive bar deltas across the selected period. An imbalance highlight compares opposing volume using the chart’s chosen ratio and price-level pairing. For a diagonal comparison, ask volume at one price is compared with bid volume one tick below.
Each trade’s side comes from the feed’s aggressor flag or, where the feed has none, from a trade-and-quote classification. Read the bid-ask grid as the record of who crossed the spread at each price.
How traders combine footprints with other market views
Volume profile maps traded volume over the wider price range. Market depth shows resting orders. The footprint supplies the execution detail inside each bar.
For optionable stocks and ETFs, options flow shows contract activity by strike and expiration, and the options profit calculator models a position’s payoff across price scenarios.
Limitations of footprint charts
- Prefer a feed with an aggressor flag. Where the chart infers the side from quotes, some trades land in the wrong column, so give a small delta less weight.
- Read delta as urgency. Every contract bought is also sold, so the bar’s +1,500 means buyer-initiated volume beat seller-initiated volume by 1,500 contracts. Check whether price advanced on that pressure.
- Pair the grid with market depth. The footprint records completed trades, resting orders sit on the depth ladder, and a hidden order shows up only once it executes.
- Set the imbalance ratio and pairing before the session, since a different setting flags different rows.
- Match the bar interval and data feed before comparing two footprints of the same session.
Bottom line
A footprint chart shows how much traded at each price inside a bar, and a bid-ask footprint also shows which side initiated it. Read delta and the highest-volume rows against the bar’s actual price progress, and pair the grid with volume profile and market depth so executions, range and resting orders are read together.
Clear answers
Frequently Asked Questions
Sources and Further Reading
- Charles M. C. Lee and Mark J. Ready, Inferring Trade Direction from Intraday Data, Journal of Finance 46:2 (1991), pp. 733–746
- CME Group: Trade Summary Order Level Detail
How entries are sourced, calculated and updated: editorial methodology.