Dealer Logic · DL-05 · Core

Gamma flip and zero crossings

What makes a Gamma-flip level move?

One concept per page · original written lesson · 332 prose words · authored, not installed or production-approved

What you will learn and prerequisites

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

A Gamma-flip level is a root of a positioning model: a hypothetical spot where estimated net Gamma crosses zero. It is not an exchange-designated support or resistance level. It can change even when the chart does not.

Understand the mechanism

A spot scan reprices sensitivities while assuming an inventory and a volatility-surface response. Sticky-strike and other surface conventions can produce different results. A book can have multiple roots or no root in the plotted domain.

A shallow crossing is especially sensitive to estimation changes. Reporting one precise line can hide that uncertainty.

Walk through the process

Inspect the curve around the root, not only the displayed price. Identify which inventory or IV assumptions would shift it. Record its timestamp.

Use the level as a hypothesis for observing a regime transition, not an automatic entry. Acceptance and liquidity still matter.

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

The fictional model is G(S)=10(S−100) shares per dollar. It equals −20 at 98, zero at 100 and +20 at 102. Adding +30 through a changed inventory assumption gives G(S)=10(S−100)+30, with root 97.

The root moved because an input assumption changed. No claim that spot must travel to 97 follows. The graph shows the original curve.

Open the calculation without leaving this lesson

Gamma flip and zero crossings—worked comparison

Vertical: Modeled Gamma (shares/USD)
Horizontal: Spot (USD)

1. Fictional example

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

Read the graph as a data table

Complete graph data; original fictional observations or model calculations
Spot (USD)	Fictional example
95	-50
96	-40
97	-30
98	-20
99	-10
100	0
101	10
102	20
103	30
104	40
105	50

What would invalidate the reading?

A root is not a price that must repel or attract the market. Multiple crossings and uncertain surface dynamics can defeat a single-line interpretation.

Check your understanding

Try the question before revealing its answer. These are reading checks, not trading certification or a site completion record.

Where is the root of 10(S−100)+30?

Reveal the worked answer

97.

Set the model output to zero rather than reading a price target into it.

Critical risk question

What is the critical failure to avoid?

Reveal the worked answer

A root is not a price that must repel or attract the market. Multiple crossings and uncertain surface dynamics can defeat a single-line interpretation.

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

Takeaway

Return to the question: What makes a Gamma-flip level move? State the observed facts, the assumptions and the failure condition separately.

Sources, assumptions and downloadable script

External references support definitions and conventions. Worked scenarios and prose are original. No current quotes or dealer inventory are claimed.

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