Gamma flip
The price where modeled net gamma exposure changes sign. Above it the map leans long gamma (calming), below it short gamma (amplifying).
The gamma flip, also called zero gamma, is found by adding up net gamma exposure strike by strike from the bottom of the strike ladder upward and marking the price where that running total crosses zero. Tools differ in the details, such as interpolating between strikes or re-pricing gamma at hypothetical prices.
Because it is a running total, a single strike changing sign does not move the flip by itself. The flip compares the price with the whole map: CaymanBot labels the regime Negative when the price is below the flip and Positive when it is at or above it. The flip can move when open interest changes, especially after an expiration.
Illustrative example (hypothetical numbers, not a real trade): net GEX adds up to -$3B by the 99 strike and to +$1B by the 101 strike. Interpolating, the running total crosses zero at about 100.50, so with the stock at $100 the regime reads Negative.