End-of-day momentum is when the final 30–60 minutes produce a strong, one-directional move as imbalances and negative-gamma hedging drive price into the close. It’s the opposite of the pin.

What creates it

Two main drivers: a large one-sided MOC imbalance (institutions pushing the same direction into the auction), and a negative-gamma regime (dealer hedging amplifies the move rather than damping it). When both align, the close can trend hard — a closing drive that overwhelms any pinning force.

How to recognize it

Watch the published imbalance (a big, growing one-sided figure) and the gamma regime (negative = amplifying). If price is trending into 3:30–4pm on volume with a supporting imbalance and negative gamma, you’re likely in end-of-day momentum, not a pin. The tell is that dips/rips don’t get faded — they extend.

When the imbalance is big and gamma is negative, the close doesn’t pin — it runs. Dealer hedging stops damping and starts driving.

What it means for a scalper

End-of-day momentum can be a clean trend trade — but it’s in the highest-risk 0DTE window (max gamma, wide spreads). Trade with the imbalance and regime if you trade it at all, and respect the close risk. Knowing whether you’re in a pin or a drive is the key late-day read.