The gamma flip, also called the zero-gamma level, is the underlying price at which estimated net dealer gamma changes sign from positive to negative. Above it, dealer hedging tends to dampen price moves; below it, hedging tends to amplify them.
How it works
Gamma exposure is usually quoted at the current price, but it depends on price itself. To find the flip, the same options book (the same open interest, implied volatility and time to expiry) is re-evaluated at a range of hypothetical prices above and below the current one. At each price the gamma of every contract is recomputed, typically with the Black–Scholes model, and net dealer gamma is summed. The flip is the price where that curve crosses zero, usually found by interpolating between the two grid points on either side.
Why the curve crosses zero at all: under the common convention that dealers are long calls and short puts, a falling price moves puts toward the money, so their negatively counted gamma grows while the calls' gamma shrinks. At some point below the current price the negative side outweighs the positive, and net gamma turns negative. In a market dominated by protective put buying, the flip therefore often sits below the current price when markets are calm.
Note that the flip is not the same as the strike where per-strike gamma changes sign, and providers differ in method: some hold implied volatility constant across the grid, others adjust it along the skew. Levels from different sources can differ by a few percent.
How to read it
- Above the flip. Dealers are estimated to be long gamma. Realized volatility has tended to be lower, ranges narrower and intraday moves more likely to fade.
- Below the flip. Dealers are estimated to be short gamma. Moves tend to be faster and more directional, and daily ranges wider.
- Distance matters. A price 0.5% above the flip is in a fragile regime; one 5% above is not. A flip that sits far away, or none within the range examined, suggests the regime is not close to changing.
- Crossings. A break below the flip often accompanies rising volatility, and a recovery above it often coincides with calmer trading. Neither is guaranteed.
- The level moves. The flip is recalculated as open interest, implied volatility and expiries change, and it can shift noticeably after a large monthly expiry.
For risk management, the regime is more useful for sizing than for timing: wider expected swings below the flip argue for reviewing stop distances and position size (see stop-loss and position sizing).
Worked example (illustrative numbers)
Suppose an index ETF trades at $500. Recomputing dealer gamma across a grid of prices gives:
| Hypothetical price | Net dealer gamma per 1% move |
|---|---|
| $510 | +$2.0 billion |
| $500 (current) | +$1.2 billion |
| $495 | +$0.4 billion |
| $490 | −$0.4 billion |
| $480 | −$1.5 billion |
The sign changes between $495 and $490. Interpolating linearly, zero is reached halfway, so the flip is about $492.50, roughly 1.5% below the current price. While the ETF holds above $492.50, the model points to a range-bound regime. A decline through it would put dealers, on these estimates, on the short-gamma side, where their hedging adds to selling.
Limitations and common mistakes
- It rests on estimated positioning. If the long-calls, short-puts convention is wrong for a ticker, the flip is wrong too.
- The model is static. It holds open interest and volatility fixed, while in reality both change as price moves.
- It is not a trigger. Treating the flip as an exact line that must hold, or as an automatic entry signal, overstates its precision.
- Single stocks are noisier. The concept is most established for broad index options, where dealer hedging is a large share of flow.
- Same-day options are missing. Contracts opened and closed within the session never reach open interest.
In Clear Tape
The free SPY, QQQ and IWM cards on the Options page show the gamma flip next to the current price, with a note when no flip exists within 15% of price. Pro members can chart dealer gamma by price for any stock with listed options, from 15% below to 15% above the current price, with the flip marked; see a note when price sits above or below the flip; and, in the watchlist scan, see each stock's distance to its flip. Clear Tape evaluates 41 hypothetical prices with Black–Scholes gamma and takes the sign change nearest the current price, interpolated linearly. Dealer positioning is estimated, and members see each session's closing data once the next session has opened. See pricing.
For educational purposes only. Not investment advice.