Option Pinning

Option pinning is a market phenomenon occurring near the expiration date of options contracts, where the underlying asset price tends to gravitate toward the strike price of a large volume of open interest. This happens because market makers, who have sold these options, must manage their delta risk as expiration approaches.

To remain delta neutral, they buy or sell the underlying asset as the price moves. As the price nears the strike, the delta of the options changes rapidly, forcing market makers to trade the underlying asset in a way that pushes the price closer to the strike.

This self-reinforcing mechanism creates a magnet effect, locking the price at or near the strike until the options expire. It is a critical concept in market microstructure and reflects the interplay between derivative positioning and spot price movement.

This behavior is most pronounced in highly liquid stocks or crypto assets with concentrated open interest at specific strikes. Understanding pinning helps traders anticipate volatility patterns and potential support or resistance levels during expiration windows.