I found myself watching a few videos on tastytrade.com recently... In particular their 'Market Measures' and 'Options Math' shows. They talk of "IV Rank" a lot and I wondered if anybody has come across it before and could explain exactly what it is?So far I know that it's some measure of implied volatility over some historical period of time, I think they use 52 weeks. What I can't determine is if it is some vol index type calculation similar to VIX for example that takes into account a full surface of strikes for the front options expiry, or, if it is just a measure designed to keep track of the ATM vol or something. Would be very interested to know as these guys are adamant that it is one of the most useful if not THE most useful stat that they use.

OK great thanks for that... When you say "current IV" do you know if that is just an ATM vol or is it some interpretation of IV based on a full surface of strikes?