Trading 0DTE SPX Around the Gamma Flip

On 0DTE-heavy SPX, the HVL / gamma flip decides whether the day gets pinned or trends — here is how to let it set your 0DTE bias.

On days dominated by 0DTE (zero-days-to-expiry) SPX options, the HVL — the gamma flip — is the line that decides the character of the session: above it, hedging tends to pin and mean-revert price; below it, hedging tends to let price trend and extend. Because 0DTE options have very high, fast-changing gamma, dealer hedging around them can be intense and concentrated into the single session, which makes the flip especially consequential for intraday SPX and ES traders. The practical takeaway is not a signal but a bias switch: which side of the flip you are on should change the kind of trade you look for.

Why 0DTE amplifies the gamma effect

0DTE options concentrate a large amount of gamma into a single trading day, so the hedging response to price moves is faster and more localized than with longer-dated positioning. That concentration is why 0DTE-heavy sessions can feel either unusually sticky — price pinned to a strike for hours — or unusually sharp once a key level gives way. It is the same dealer-hedging mechanism described in what gamma levels are, just compressed into the expiry day, which is exactly why reading the regime first matters so much.

Above the flip: lean toward fades and the pin

When SPX is trading above the gamma flip, dealers are generally net-long gamma and hedge against moves, so the day tends toward containment: rallies into the call wall stall, dips get bought, and price gravitates to magnets. In this regime your higher-probability 0DTE ideas are typically fade setups at the walls and plays that respect a magnet as a target rather than breakout trades that need price to run. The regime does not guarantee a quiet day, but it tilts the odds toward mean reversion, so size and expectations should match that.

Below the flip: respect the trend

When SPX drops below the gamma flip, dealers are generally net-short gamma and hedge with the move, so volatility expands and trends extend — the environment where fading blindly is most dangerous. Here your bias should flip toward trend-continuation and breaks of levels rather than fades of them: a put-wall break below the flip can lead to acceleration toward the next strike. The single most useful habit in 0DTE SPX is to check, before every trade, whether you are above or below the flip — because the same level can be a fade in one regime and a breakout in the other.

Fitting it into the framework

Using the flip to set your 0DTE bias is one component of the full method, not a standalone system. It works best combined with wall-reading and confluence, all covered in the pillar, how to trade SPX / ES with gamma levels. The daily Gamma Axis report gives you the HVL and the walls before the open; start with the free daily levels to learn the regime, and the €19.90/mo Supporter plan delivers them each morning with the auto-updating indicator so the flip is already on your ES chart when the bell rings.

FAQ

What exactly is the gamma flip?

It is the price at which aggregate dealer gamma positioning switches from net-long to net-short. Above it, hedging tends to dampen moves; below it, hedging tends to amplify them.

Is 0DTE trading riskier than other SPX trading?

0DTE options decay and change value very quickly, which concentrates both opportunity and risk. This article is educational and not a recommendation to trade 0DTE; manage size and risk accordingly.

Does the flip move during the day?

It is computed from the session's positioning, but intraday flows can shift the effective regime. Treat a cross of the flip as a reason to re-check your bias, not as a one-time morning read.