# Gamma regimes are model states

**DL-04 · Dealer Logic · Core**

**Lesson question:** What can a positive or negative regime label establish?

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

A Gamma regime summarizes estimated curvature in a selected option inventory. It is context for potential hedge feedback, not a complete description of the market. Positive Gamma can coexist with a trend if other flows dominate; negative Gamma can coexist with quiet trade.

## Understand the mechanism

The estimate depends on included products and expiries, position allocation, spot, time and volatility assumptions. A near-zero total can mean genuinely small exposures or large opposing exposures cancelling locally.

Public open interest does not identify the complete dealer/customer split. New trading and repricing can change the result intraday.

## Walk through the process

Ask for methodology, timestamp and sensitivity to assumptions. Compare the model with the actual auction without requiring price to obey it.

A useful note reports sign, scale, uncertainty and what observed behavior would challenge the interpretation. 'Unknown' can be the correct conclusion.

## 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

Two fictional allocations of the same chain produce +50,000 and −20,000 shares per dollar of Gamma. A one-dollar rise would imply 50,000 shares of selling under the first and 20,000 of buying under the second, assuming active neutrality.

The disagreement is model uncertainty. Averaging the labels does not establish a safe range or a current dealer fact. The chart compares the signed estimates.

## Graph: Gamma regimes are model states—worked comparison

**Horizontal:** Inventory-allocation model  
**Vertical:** Gamma (shares/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-04.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

Many decimal places do not repair uncertain inventory ownership, stale data or excluded products.

## Check your understanding

### Can a quiet session prove positive dealer Gamma?

**Answer:** No.

**Why:** Many liquidity and inventory states can produce quiet price behavior.

### What is the critical failure to avoid?

**Answer:** Many decimal places do not repair uncertain inventory ownership, stale data or excluded products.

**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 a positive or negative regime label establish? 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)