Options · evergreen
Positive vs Negative Gamma: Why the Sign Matters
Negative gamma means dealers chase and amplify swings. Positive gamma dampens. Thursday vs Friday QQQ shows both regimes on the Cos map.
As of Mon Sep 28, 2026, ~1:00 AM PT. Worked examples use Thu Sep 24 and Fri Sep 25 US cash. BOOK FACT · NOT A TICKET · SIMULATED RESEARCH
Negative gamma means the estimated dealer book is short gamma, so hedges tend to chase price and amplify swings. Positive gamma is the opposite job: dealers fade extremes and dampen the tape. Neither sign is bullish or bearish. Both describe the character of the move, not where it has to finish.
Thursday Nasdaq opened under a put wall in a Negative Gamma book and still closed higher.
Friday the same index sat in Positive Gamma, closed under the call wall and above the flip, and the tape felt sticky instead of stretched.
Same hedge engine. Opposite job.
What does negative gamma mean in options?
Dealers take the other side of a lot of listed options. They hedge in QQQ, SPY, or the futures. Gamma is how fast that hedge size changes when price ticks. When the estimated book is short gamma, a down-move can force more selling. An up-move can force more buying. The hedge chases. Swings can outrun the news.
That is negative gamma: an amplifying regime. It is not a sell ticket. Thursday proved the point. Cos stamped Negative Gamma at 11:14 PT with net GEX about -$331 million, and QQQ still closed 741.10, above the flip.
Parent map: What is gamma exposure?.
What does positive and negative gamma mean?
Two signs. One mechanism.
Positive gamma (dealers long γ): sell rips, buy dips. The hedge leans against the move. Realized swings often shrink. The tape can feel bored.
Negative gamma (dealers short γ): chase. Sell into weakness, buy into strength. Ranges can feel too big for the headline.
GEX maps are estimates from listed open interest and an assumption about who holds what. Dealers' true inventory is not public. Cos stamps a time and treats the print as a map.
Three landmarks show up on every Cos sheet:
- Put wall (P1): heavy put-gamma strike. Below it in a short-gamma book, hedges can speed both directions.
- Call wall (C1): heavy call cluster. Rallies often slow there because the hedge sells into strength.
- HVL / flip: Cos's name for the estimated zero-crossing. Above it, dampening is more likely. Below it, amplification is more likely. Gamma flip and call-put wall explainers are next after the parent hub.
What is a positive gamma environment?
A positive gamma environment is when the estimated dealer book is long gamma near the current price. Hedges fade extremes. Moves still happen. They often look smaller than the story on the screen.
Friday Sep 25 was the classroom next to Thursday's amplifier.
QQQ cash: open 742.83, high 745.92, low 739.64, close 744.5.
Cos map at 12:14 PT: call wall 745, HVL 738, put wall 736. Net GEX about +$591 million. Profile: Positive Gamma. Cash closed UNDER C1 and ABOVE HVL.
SPY closed 771.35 (walls 772 / 767 / 764, net about +$866.2M). VIX about 14.86-14.87. Sticky-tape look: hedge more likely to lean against the move than chase it.
What does a negative gamma day look like?
Thursday, September 24, 2026. QQQ: open 735.29, high 742.66, low 734.62, close 741.10.
Cos map at 11:14 PT: put wall 736, HVL flip 739, call wall 742. Midday profile: Negative Gamma. Net GEX about -$331 million.
QQQ opened under 736 and printed 734.62. In a short-gamma regime, a break under a put wall is where dealer hedges can push with the tape.
The wall got reclaimed. Cash crossed 739. The high 742.66 tagged toward C1 742. Close 741.10 sat above HVL 739 and under C1 742.
Negative gamma did not call a down day. It described the morning's extra slack, then the repair. SPY closed 767.18. VIX about 15.67.
Two regimes for the next session
A. Positive-gamma hold above the flip. Price stays above the stamped HVL while net GEX is estimated positive. Dealer hedges are more likely to dampen. Moves can still print. They often look smaller than the headline. Friday's close under C1 745 and above HVL 738 is that corridor.
B. Negative-gamma break under the put wall. Price loses P1 while the book is still estimated short gamma. Dealers chasing can make the range feel too big for the news. Thursday's open under 736 was that setup. The reclaim later showed the map can repair inside the same session.
Neither path is a buy or a sell.
Levels from the Cos book
Thu Sep 24 map (11:14 PT), Negative Gamma class
- QQQ Above 742 (C1): testing the call wall after the repair.
- Between 739 and 742: afternoon corridor. Flip held. Call wall not accepted on the close.
- Below 736 (P1): put wall lost again. In a still-negative book, swings can stretch.
Fri Sep 25 map (12:14 PT), Positive Gamma contrast
- QQQ C1 745 / HVL 738 / P1 736. Close 744.5 UNDER C1 / ABOVE HVL.
- SPY C1 772 / HVL 767 / P1 764. Close 771.35.
Interim until the next Cos stamp. Open interest rewrites the map.
What should you watch next?
- Which sign is stamped at the open. Positive vs negative gamma sets whether hedges are more likely to fade or chase.
- The put wall and the flip. Holding the HVL keeps a repaired read. Losing P1 in a still-negative book is when the amplifier tends to show up.
- A new Cos stamp. Thursday's 11:14 PT and Friday's 12:14 PT reads are not Monday's book.
- FOMC on the calendar, not as a GEX forecast. Next meetings: October 27-28 and December 8-9, 2026. Event days can flip a gamma regime because new options print and implied vol jumps.
- Overnight into Mon ~1 AM PT (Yahoo): ES ~7769.75, NQ ~30606, VIX ~16.2. Soft fade, not a spike.
FAQ
What does negative gamma mean in options?
The estimated dealer book is short gamma, so hedges tend to chase price and amplify swings. It maps volatility character, not direction.
What does positive and negative gamma mean?
Positive: dealers fade extremes and dampen. Negative: dealers chase and amplify. Same hedge engine. Opposite job.
What is a positive gamma environment?
A session where estimated dealer gamma is positive near the current price. Hedges lean against the move. Friday Sep 25 QQQ (net about +$591M, close under C1 / above HVL) is the Cos classroom.
Is negative gamma bearish?
No. Thursday was Negative Gamma and QQQ still closed higher. The sign describes how hedges may behave if price gets there, not where the close must land.
The aha
People hear negative gamma and reach for a red candle. That is the wrong reflex.
Negative gamma is an amplifier. Positive gamma is a dampener. Thursday opened under 736 in Negative Gamma and closed 741.10 above the flip. Friday sat in Positive Gamma and closed sticky under the call wall. The map did not fail either day. The people who asked it for direction did.
Read the sign as a job description for the hedge. Fade or chase. Then the walls look like crowded strikes with a mechanical job.
Full research archive: https://cosanalyst.com/articles/positive-vs-negative-gamma/
Parent hub: https://cosanalyst.com/articles/what-is-gamma-exposure/
BOOK FACT · NOT A TICKET
SIMULATED RESEARCH
Not financial advice. GEX is an estimate. Dealers' true inventory is not public. Levels are a map, not a ticket.