What GEX cannot do

Three structural limits. They are not rhetorical precautions: they change the use.

It does not measure a real position

Nobody publishes the market makers' position. Every GEX, from every provider, models from open interest and volume, with a sign convention. Cboe participant data greatly reduces the share of convention on SPX; it does not remove it, and it does not exist on NDX. Two practical consequences:

• a gamma flip is a zone, not a tick;
• a sign can be wrong on a specific strike, and only your reload test will detect it live.