0DTE and Volatility Triggers

Gamma is highest for at-the-money options near expiry. A 0DTE strike sitting right at price can flip from near-zero delta to near-full delta in minutes. Dealers hedging that convexity must trade the underlying aggressively, which is why price can sit dead for an hour and then travel a full range in fifteen minutes with no news.

When dealers are long 0DTE gamma around a heavily traded strike, hedging pulls price back toward it repeatedly. The result is the familiar afternoon pin: shrinking ranges, repeated failures at the extremes, and a close near a round strike. Fading small extensions works well in this state; chasing breakouts does not.

A volatility trigger is the price where net dealer gamma flips sign for the current expiry. Above it the market is pinned, below it hedging turns pro-cyclical and ranges expand. Tracking that level intraday is more useful than any single wall, because it tells you which behaviour to expect for the next hour.

0DTE positioning builds in waves: the open sets the initial structure, the European close and the 11:00 ET window often bring repositioning, and the final hour is dominated by charm-driven unwind. Expect the gamma map to shift after each of these windows, which is exactly why FTS republishes level packages through the session instead of once a day.

Know whether you are above or below the volatility trigger before you take a trade. Treat large 0DTE strikes as magnets, not as walls that never break. And avoid holding mean-reversion positions through a regime flip — the same setup that was high probability twenty points ago can become the worst trade of the day once hedging turns pro-cyclical.