An equity index swap in which the equity return is linked to the greater of two stock indexes. For example, an equity swap may have an equity return leg that pays either the S&P500 return or the Nikkei return, whichever is higher. The structure of this swap is depicted below:

This swap is, in general, more attractive to the equity receiver than a swap linked to a single index, as the former gives the option to choose between two sources of equity return, not just one. Therefore, the two-index equity swap will command a higher swap coupon relative to a single index equity swap.