# Volume and depth

**FUT-15 · Equity Index Futures · Core**

**Lesson question:** What can participation data prove?

Original fictional examples; educational writing, not live market data, orders or production approval.

## By the end

- Explain the mechanism in the lesson question.
- Reproduce the worked comparison and recognize its failure case.

**Prerequisites:** FUT-01

Volume measures trades completed over a window. Depth describes displayed orders now. Both inform liquidity but neither reveals all participants' intentions. Large volume does not automatically mean bullish conviction because every trade has both sides.

An informative reading combines movement, activity and available execution.

## Understand the mechanism

A high-volume interval can reflect repricing or disagreement. Little price progress despite heavy activity may prompt an absorption hypothesis, but identifying it requires more detail than an aggregate bar.

Displayed orders can be withdrawn or replenished. Daily volume is not guaranteed capacity at one price during stress.

## Walk through the process

Compare like sessions and intervals. Observe whether a level holds, spreads widen and depth replenishes. Estimate the proposed order's costs rather than using ideal midpoint fills.

Treat participation as a context layer, not a mechanical buy or sell command.

## Operational boundary

All prices, portfolio values and account balances are fictional. Real contract calendars, broker requirements and available liquidity must be checked for the instrument actually traded. The example's mathematical hedge or payoff is not an execution guarantee.

## A worked example

Two fictional intervals each trade 10,000 contracts. One travels twenty points and holds the new area; the other travels two and repeatedly returns to the center. Equal volume produced different auction results.

The graph compares net movement. It does not establish trader identity or the next direction. A backtest must model executable fills, not just the favorable high or low.

## Graph: Volume and depth—worked comparison

**Horizontal:** Equal-volume interval  
**Vertical:** Net directional progress (points)

Fictional data from the written example. The chart organizes the comparison; its shape is not a forecast.

Complete numerical data are embedded in `scripts/equity-futures/FUT-15.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

Equating volume with direction or assuming displayed orders will remain can produce false confidence and worse fills.

## Check your understanding

### Does equal volume imply equal directional progress?

**Answer:** No.

**Why:** The example has twenty versus two points despite identical volume.

### What is the critical failure to avoid?

**Answer:** Equating volume with direction or assuming displayed orders will remain can produce false confidence and worse fills.

**Why:** Explain this risk before treating the example as a decision rule. A correct calculation does not guarantee a favorable market outcome. **Critical risk check.**

## Takeaway

Return to the question: What can participation data prove? State the observed facts, the assumptions and the failure condition separately.

## References and provenance

The cited references support definitions and conventions. The teaching prose, tickets and numerical scenarios are original; they are not attributed as historical market observations.

- [CME Introduction to Futures](https://www.cmegroup.com/education/courses/introduction-to-futures)

- [CME Micro E-mini overview](https://www.cmegroup.com/education/courses/micro-e-mini-futures/micro-e-mini-futures-products-overview)