Dealer gamma: why some days chop and others trend

How options dealers hedge, what positive and negative gamma regimes mean, and why estimates come with assumptions.

By AnkushAI Editorial, Education team · Oct 30, 2026 · 1 min read

Market makers who sell options to the public usually hedge so they are not betting on direction. How they hedge can influence how the underlying moves, especially in heavily traded products like SPY and QQQ.

The basic mechanism

A dealer who is short a call is exposed if the stock rises, so they buy shares to hedge. As price moves, the option's delta changes (that is gamma), so the dealer keeps adjusting the hedge.

Positive gamma regime

When dealers are net long gamma, they hedge by selling into rallies and buying into dips. That flow pushes against the move, which can mean tighter ranges and more mean reversion.

Negative gamma regime

When dealers are net short gamma, they hedge by selling into declines and buying into rallies. That flow goes with the move, which can mean larger, faster swings.

Levels people watch

• Gamma flip: the price where estimated net dealer gamma changes sign.
• Call wall and put wall: strikes with large call or put gamma that can act like magnets or barriers.
• The largest single strike, sometimes called the king node.

The assumptions

Public data does not say who is long or short each contract. Gamma exposure (GEX) estimates assume who holds what, usually that customers buy puts and sell calls, so the numbers are models, not facts. Use them as context next to price levels, not as a forecast.

Positioning describes the terrain. Price still decides which way the road goes.

Educational, not financial advice.

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