Thanks for that suggestion, I'll certainly look in to it. Why would I want to look at ATM-constant implied vol instead of ATM-non-constant implied vol?Why is it important that they are ATM?Thanks,

<t>Here is a scenario:You have an equity underlier (lets call it X) which you are trading based on a volatility surface. You also have a list of other equity underliers with their own, unique, vol surfaces. Your task is search through that list of other underliers to find the vol surface which is th...