# Write an auditable dealer note

**DL-16 · Dealer Logic · Core**

**Lesson question:** What makes a positioning explanation useful rather than persuasive-sounding?

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:** DL-01

An auditable note identifies the data time, model assumptions, signed exposure, conditional hedge direction, competing liquidity and invalidation. It should be concise enough to challenge, not hidden behind acronyms.

The objective is to explain one possible flow channel, not promise a market outcome.

## Understand the mechanism

Separate what is observed, modeled and hypothesized. State units before size. Compare a plausible small shock with the implied hedge change. Then identify the assumptions most likely to fail.

Daily volume is not guaranteed depth at the exact execution time. A flow estimate that seems small or large needs a relevant liquidity comparison.

## Walk through the process

Finish with a conditional statement and a no-trade alternative. Stale, conflicting or absent evidence can justify waiting. Review the note after the event without rewriting its original terms.

A useful hypothesis admits what would reduce confidence before the market reveals the answer.

## Evidence boundary

The arithmetic is original conditional teaching material, not a measurement of current dealer positions. The cited Cboe research is historical product-specific evidence, not a live inventory feed. Model outputs should remain distinguishable from observed market facts.

## A worked example

A fictional note says: 'At the observation, model A estimates +40,000 shares/dollar Gamma under its stated allocation. A +0.50 move implies about 20,000 shares of selling to remain neutral. Persistent acceptance beyond the prior region would weaken a simple mean-reversion interpretation.'

Arithmetic is −40,000×0.50=−20,000. The note does not establish that the trade occurs at a precise time or controls price. The graph varies the shock.

## Graph: Write an auditable dealer note—worked comparison

**Horizontal:** Spot change (USD)  
**Vertical:** Conditional hedge change (shares)

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

Complete numerical data are embedded in `scripts/dealer-logic/DL-16.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

Deleting the assumption words turns conditional research into an unsupported signal. An exact time or price forecast needs more evidence than the hedge equation.

## Check your understanding

### What is the conditional hedge change for +40,000 Gamma and a +0.50 move?

**Answer:** Sell about 20,000 shares.

**Why:** It follows only for the assumed inventory and active neutrality.

### What is the critical failure to avoid?

**Answer:** Deleting the assumption words turns conditional research into an unsupported signal. An exact time or price forecast needs more evidence than the hedge equation.

**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 makes a positioning explanation useful rather than persuasive-sounding? 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.

- [OIC Greeks](https://www.optionseducation.org/advancedconcepts/understanding-options-greeks)

- [Cboe 0DTE positioning study, May 2025](https://www.cboe.com/insights/posts/0-dt-es-decoded-positioning-trends-and-market-impact)