Gamma exposure estimates the aggregate gamma position of options dealers from open interest across a chain. Its sign describes how dealer hedging interacts with price: positive gamma dampens moves, negative gamma amplifies them.
Derived levels include the gamma flip (where the aggregate changes sign), the call wall, and the put wall. The estimate rests on an assumption about which side dealers hold, an assumption that is index-shaped and unreliable for single names with directional order flow, so regime interpretations apply to index products. The full treatment, including what a controlled test found about wall effects, is in dealer gamma exposure.