When you buy an option, a dealer (market maker) usually sells it to you. They don't want directional risk, so they hedge — buying or selling the underlying to stay neutral. That hedging is real order flow, and in size it moves price. No conspiracy, just mechanics.

The delta hedge

An option has a delta — its price sensitivity to the underlying (delta explained). To neutralize the delta of options they've sold, dealers take an offsetting position in the underlying. As price moves, the option's delta changes (that's gamma), so dealers must continuously re-hedge, and that ongoing buying and selling is a persistent force in the tape.

Absorbing vs amplifying

The direction of that force depends on the dealers' net gamma. Long gamma (positive): they hedge against the move — selling rallies, buying dips — which dampens volatility. Short gamma (negative): they hedge with the move — buying rallies, selling dips — which amplifies it (positive vs negative gamma).

Dealers aren't betting on direction — they're forced to trade it. That forced flow is why the same level holds one day and shatters the next.

Why it matters to you

This flow is why price pins to big strikes (gamma walls), why some days grind and others lurch, and why the gamma-flip level is such a pivotal read (the gamma flip). You can't see dealer hedging directly, but its footprint is all over the tape, and reading it is exactly what Analyst does. See charm and vanna.