What Is Cross Gamma?

The basic idea

Ordinary gamma is often read within one underlying. Cross gamma extends the question: how can a move in one related underlying change the sensitivity or hedging response associated with another? The answer depends on the contracts, maturities, correlations, and assumptions in the model.

How to read it responsibly

Start by identifying the relationship being described and the time window. Then compare the interaction with the single-underlying structure and current price context. A cross-asset relationship can add context without replacing the primary map.

• Name both underlyings and the contract scope.
• Check whether the relationship is stable or changing.
• Keep the primary underlying's own structure in view.

What it cannot establish

Cross gamma does not establish a fixed hedge ratio, a guaranteed correlation, or a trade direction. Sparse data, changing positioning, and model simplifications can all make the relationship weaker than it appears.