Option Pinning

Option Pinning is the broader umbrella phenomenon that the Max Pain Gravity Effect is a specific case of. Where max pain gravity refers only to drift toward the single calculated Max Pain strike, pinning can occur around any strike that has built up unusually heavy open interest, identifiable on an option chain as an OI wall, whether or not that strike happens to be the max pain point for the series.

The mechanism is rooted in delta hedging by market makers and large option writers who are short options at the pinning strike. As price approaches that strike price near expiry date, gamma near the money rises sharply, so writers must trade increasingly large quantities of the underlying (or futures) to stay delta-neutral for even small price moves. If the underlying rises above the strike, their hedging typically involves selling; if it falls below, buying, a self-correcting flow that can hold price near that level through the final session, particularly in the last hour of trading.

On the NSE, pinning is observed most reliably in the most liquid index contracts, Nifty 50 and Bank Nifty weekly expiries, where option writer participation is deep enough for hedging flows to matter. It is far less reliable in individual stock options, especially those with thin volumes, where a handful of large orders can easily break the pin. Retail traders use strikewise open interest or multistrike open interest views to spot likely pinning candidates ahead of expiry day.

The main gotcha is that pinning is a late-stage, expiry-day phenomenon that can be instantly overridden by news, a large institutional order, or a broad market move, it should never be treated as a reason to hold a position into expiry expecting price to stay put. Many experienced traders use it only to gauge which strikes are likely to see limited movement, not as a directional or income-generating strategy by itself.