# Compare dealer models with the auction

**DL-12 · Dealer Logic · Core**

**Lesson question:** What happens when the model and price disagree?

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

Price structure records observed trade; dealer analytics estimate one possible source of flow. Neither should erase the other. A useful interpretation records what the model suggested and what price actually did.

Disagreement can reveal a weak estimate, a small effect or stronger competing forces.

## Understand the mechanism

A positive-Gamma hypothesis may imply opposing hedge flow after small moves. Persistent acceptance in a new region can still occur if external orders dominate. The inference should be conditional rather than protected from every possible outcome.

Do not retrofit the eventual reversal as proof while ignoring a large earlier excursion that invalidated the original trade.

## Walk through the process

Map instruments and timestamps consistently. Write the model's expected behavior and the observation that would challenge it. Classify dealer values as observed or inferred.

Calculate trade risk from the instrument and executable conditions, not from faith in the model line.

## 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

An illustrative estimate suggests dampening near 100. Price trades 100.20, 100.80, 101.40 and 101.30 with activity concentrated above the old area. Under the declared acceptance rule, the simple pinning hypothesis is not describing the current auction.

The correct response is reassessment, not an accusation that the market must return. The graph records the observations, not a verified dealer flow.

## Graph: Compare dealer models with the auction—worked comparison

**Horizontal:** Completed observation  
**Vertical:** Spot (USD)

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-12.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

Letting a model override persistent price acceptance can keep a trader fading a genuine trend. A hypothesis without an invalidation is not testable.

## Check your understanding

### What should happen to confidence in pinning when price persistently accepts away?

**Answer:** Reassess or reduce it.

**Why:** The observation challenges the local narrative.

### What is the critical failure to avoid?

**Answer:** Letting a model override persistent price acceptance can keep a trader fading a genuine trend. A hypothesis without an invalidation is not testable.

**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 happens when the model and price disagree? 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)