options · desk note
SPY Friday Gamma: +$4.78B Thursday, −$0.93B Friday
As of Friday 28 Aug 2026 close, SPY weekly options expiration positioning prints gamma NEGATIVE. An independent EOD book flipped from +$4.78B Thursday to −$0.93B Friday. Spot ~769.35. Cos does not print G-D+.
What Cos will print
An independent end-of-day book flipped from +$4.78B Thursday to −$0.93B Friday. That is a sign change in one book over one session. It is not a Cos fill, not a premium, and not a paper ticket. Spot ~769.35 is the cash neighborhood Cos will carry for that close.
Delta sign is not agreed across books. Cos does not print G-D+. We will not flatten two disagreeing dealer books into one Cos-verified headline.
Gamma = how far. Delta = which way. Until the books agree on the sign of delta, a single “positioning” number is a vendor claim, not a Cos figure.
Thu +$4.78B → Fri −$0.93B. Spot ~769.35. No G-D+. Book fact · not a ticket.
This is structure context for the Friday map. It is not a Sector Selector play and not an invitation to chase an expiration print. Health Care still led that map: Robustness is the edge.