Monthly opex today. Quick one for the people who keep asking “why does it move like that on Fridays”.
Today’s dealer gamma map for SPX:
- Call wall: 7,900
- Put wall: 7,650
- Zero gamma flip: \~7,729
- Net GEX: −$7.41B (16th most negative of the 59 sessions on record since July)
At 11:30 ET SPX crossed below 7,729 into negative gamma, and it’s now sitting a few points above the 7,650 put wall.
Why you care: above the flip, dealers (on the usual assumption about how they’re positioned) hedge against the move. They sell rips and buy dips, so things feel sticky. Below the flip it flips: they hedge with the move, so moves get bigger. Same index, different physics. That’s why the morning chopped and the afternoon has range.
What it’s not: a prediction. Gamma tells you how hedging flow behaves, not which direction price goes. Open interest shows a contract exists, not which side a dealer is on. Anyone selling you GEX as a crystal ball is selling you a crystal ball.
Disclosure: I made the free site these numbers come from (squawkflow.com, no signup, no paywall). Got tired of paying $100+/mo to see a wall. Roast it, tell me what’s wrong, I fix stuff the same night.