Gamma flip, plainly — a one-paragraph definition, then two real days

Most people meet the gamma flip and take away this:

"Above the flip it goes up, below the flip it goes down."

That is not what it says. It is easy to see how the idea takes hold, though, because days that fall hard below the flip are real and memorable.

So this piece keeps the definition to one paragraph and spends the rest on two days that actually happened — 1 and 2 September 2026, back to back. They ended in opposite ways.

📎 Why dealers behave this way — the chain from delta through hedging and gamma to GEX — is laid out in Gamma flip — why the same news gets absorbed on one day and amplified on the next. This piece builds on top of it.

1. The definition, in one paragraph

Options sit in the market, and the dealers on the other side of them do not want directional exposure, so they keep adjusting a hedge. The direction of that adjustment flips depending on where the index is trading. Above a certain price the dealers sell into strength and buy into weakness, which dampens movement. Below it they buy into strength and sell into weakness, which extends movement.

The price where that behavior reverses is the gamma flip.

If you keep one thing from this section, keep this:

What the gamma flip tells you	What it does not
Whether today's moves get damped or extended	Whether the market goes up or down
Roughly where price meets resistance	Whether that resistance holds

It describes character, not direction.

2. Why the "above means up" reading takes hold

Below the flip, declines get amplified. So "below the flip" gets filed away as "the day it fell."

But amplification runs both ways. A bounce that starts below the flip gets amplified just as much. People simply remember the sharp declines longer.

Below the flip does not mean "it goes down." It means "once it moves, it travels."

3. Two real days — 1 and 2 September 2026

Two consecutive sessions. Here are the flip levels and what actually happened.

	Tue 1 Sep	Wed 2 Sep
Gamma flip that day	7,675	7,635
Open	7,635.47 — 39.5 pt below the flip	7,634.58 — 0.4 pt below the flip (effectively on the line)
High	7,663.63	7,681.19
Low	7,611.20	7,633.62
Close	7,631.47 — 43.5 pt below the flip	7,666.60 — 31.6 pt above the flip
Range	52.4 pt	47.6 pt
How the day ended	New 20-day low	Stopped 1.4 pt below the flip, then turned (+33.0 pt off the low, +35.13 pt on the close vs the prior day)

On 1 September the index never traded above the flip at any point. Even the high of 7,663.63 sat 11 pt below it. An attempt to fill the gap in the morning gave way in the afternoon, and the low of 7,611.20 set a fresh 20-day low.

On 2 September the index opened 0.4 pt below the flip, effectively on the line. The low came in at 7,633.62 — 1.4 pt below the 7,635 flip — and turned there. Price crossed above the line during the session and the close finished 31.6 pt above it.

🔑 The gap between the low and the flip was 1.4 points. On an index in the 7,600s, that is 0.02%.

4. The part that did not match what I expected

Something only became visible once I put the two days side by side. I am writing it down as it is.

The daily ranges were nearly the same. 52.4 pt and 47.6 pt.

If you have memorized "above the flip is quiet, below the flip is wild," these two days do not support that sentence. The distance traveled was comparable.

What differed was not the distance. It was where the move stopped.

	1 Sep	2 Sep
How far it moved	52.4 pt	47.6 pt — comparable
Where it stopped	It didn't stop — new 20-day low	1.4 pt below the flip

So this is how I filed the two days:

The gamma flip says more about where a move stops than about how far it travels.

⚠️ The sample is two days. This is an example, not a validated result. Until I have counted 30 sessions, I do not trade on it.

5. What I actually do in the morning — three lines

There is no elaborate procedure. I write down three lines.

① today's gamma flip     = ______
② price above or below   = ______
③ distance to the flip   = ______ pt

Then I spend the day watching only whether ② changes.

Line ③ earns its place. Sitting two points from the flip and sitting forty points from it are entirely different situations, and if I only record ②, the two look identical. 2 September was exactly that kind of day: it opened 0.4 pt from the line — technically below it — and crossed above within the session. With that little room, price moves either way.

🚨 Why I do not take the pre-market number at face value

The sign of GEX depends on which side of the flip price is currently on. A pre-market snapshot is usually calculated off the previous close.

That is what happened on 2 September. The pre-market figure was negative — because the calculation was anchored to the prior close of 7,631.47, which sits below the 7,635 flip. Once the session opened and price traded above the flip, the character changed.

A pre-market sign is yesterday's sign. Today's has to be read after the open.

📎 That said, brushing the line intraday and settling on the other side of it are different things. Whether a cross holds is still something I judge on the close — as set out in section 7 of the earlier post.

6. What I still do not know — and what I did that day

Written down honestly.

• The sample is two days. The "where it stops" idea is still an observation, not a statistic
• The flip did not set direction. The decline on 1 September had its own causes in the news and the flows that day. The flip helps explain how far a move ran, not why it started
• Live is far messier than hindsight. On the morning of 1 September the gamma reading came in under my own threshold (|net GEX| below 2,000), so I started the day with "gamma regime: undetermined" written at the top of the page. It looks tidy in the table above. It was not tidy that morning

And one more.

On 2 September I read the structure correctly and traded against it. I had written "above the flip, expect a range" in the morning, and during the session I repeatedly put on positions that needed the market to fall. The flip held and the index rose.

Reading a market and acting on that reading are separate skills. Understanding an indicator does not carry over into the day's execution on its own. That is what I learned that day.

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※ This piece describes the structure of an indicator and my own observations. It is not investment advice and not a recommendation to buy or sell any security. The sample here is two sessions. The prices and levels quoted are from 1–2 September 2026, and the gamma flip is recalculated every day. You are responsible for your own decisions and their outcomes.