How gamma and dealer hedging move the market

In this guide, Rader Trader makes a claim that sounds like hyperbole until you follow the mechanics: in 2026, a single options concept — gamma — has become one of the biggest forces driving day-to-day price action, and most retail traders ignore it because they assume it is too abstract to matter. The video’s real subject is not the Greek itself but the people whose hedging it governs: the market makers. Once you can picture what dealers are forced to do to stay balanced, a lot of otherwise random-looking intraday behaviour starts to look predictable.

What gamma actually is

Gamma is a second-order options Greek. Delta, a first-order Greek, tells you how much an option’s price moves when the underlying moves a dollar. Gamma measures how fast that delta itself changes — the acceleration of delta. It peaks for at-the-money options and tapers as a contract moves deep in or out of the money. On its own that is a piece of pricing math; you would never sit and stare at gamma to place a trade. It becomes useful only when you use it to model someone else’s behaviour.

Why it moves the market

Market makers provide liquidity: they take the other side of whatever order arrives, and they try to stay directionally neutral rather than bet on where price goes. To neutralise the delta they pick up from an options inventory, they buy or sell the underlying stock — sell a 0.30-delta call, buy 30 shares against it. But delta drifts as the market moves, and gamma is what tells the dealer how fast that hedge will fall out of balance, and therefore how aggressively they must buy or sell shares to re-balance.

This used to be a footnote. Since the 1973 arrival of the Black–Scholes model and the first listed options exchange, options volume has grown exponentially, and with it the sheer size of dealer hedging flows. The video’s central argument is that those flows have crossed a threshold: dealer hedging is no longer noise around the real market — on many days it is the market’s marginal buyer and seller.

Two regimes: positive and negative gamma

Everything hinges on which side of the options book dealers are holding, because that flips the direction of their hedging.

Positive gamma is when dealers are net long options. To stay balanced they sell the underlying as it rises and buy it as it falls — leaning against every move. The effect is stabilising: ranges compress, dips get bought, rallies get faded, and the tape grinds inside a tight equilibrium.

Negative gamma is when dealers are net short options, and it inverts the whole picture. Now they must sell as price falls and buy as it rises — hedging with the trend. A move feeds on itself: selling begets more dealer selling in a reflexive, self-reinforcing spiral that continues until sellers are exhausted. This is the mechanical reason behind the old line that markets “take the staircase up and the elevator down” — the slow climb is positive gamma, the violent flush is negative gamma.

Reading it: net-gamma charts and the flip

Dealer positioning can be estimated from open interest — how many contracts sit at each strike, which is public data — and plotted as a net-gamma chart of positive and negative levels. The single most important line on it is the gamma flip (the zero-gamma level, often labelled the GEX flip): the boundary between the two regimes. Cross it and the character of the market genuinely changes. Because the S&P 500 complex dwarfs everything else in dealer options positioning, the video’s shortcut is to draw the flip and the largest positive and negative levels on SPX or SPY and let the rest of the market follow.

The regime then shapes what to trade. In positive gamma, indices are pinned, so the edge migrates to individual names and daily breakouts — when the index feels calm, participants feel free to chase single stocks. In negative gamma, the indices themselves come alive, moving far more relative to their market cap than usual, which favours index trades, breakdowns, and volatility/range plays.

Three strategies built on gamma

The back half of the video lays out three setups the presenter says he trades professionally:

1. The flip “waterfall.” After an extended positive-gamma rally, the first close back into negative gamma — ideally a pre-market gap below the flip — sets up two trades: an opening-drive short (an opening-range or pre-market-low break) and, after a bounce that stays below the flip, an “afternoon roll” short into the 11:00–1:00 chop, playing for a leg lower.
2. Option Volume Imbalance (OVI). Open interest only updates once a day, so it misses intraday flow. His OVI tool scores live call-versus-put volume by each order’s likely gamma impact, then ranks the reading against a year of history — high quality and high quantity together is the signal that a breakout is genuinely supported by dealer hedging rather than by empty price movement.
3. Gamma and time. Gamma grows more sensitive as expiration nears, so dealers hedge harder. Usually that pins price into expiration; occasionally, if positioning snaps, it produces a waterfall. He uses this to time capitulation reversals in over-extended names (which he finds bottom disproportionately on Thursdays and Fridays, near expiry) and to frame the quarterly OPEX cycle, where volatility tends to compress into the big March/June/September/December expirations.

The through-line is a mindset shift rather than a single indicator: stop watching price in isolation and start asking what the dealers on the other side of the options book are obligated to do next. Two of the three setups also lean on tooling and data — net-gamma levels and real-time option flow — that a standard charting platform does not provide out of the box, which is worth knowing before trying to reproduce them.

This is a summary for readers deciding whether to watch, and nothing here is financial advice. The strategies are presented from the author’s own trading experience, not as independently verified edges — treat them as hypotheses to test, not recipes to follow.

Summary of the video “Gamma Trading: The Edge Market Makers Wished You Didn’t Know” by Rader Trader. Watch the full guide above for the charts and worked examples.