IV's are supposed to be indicators of the actual value of the ETF's underlying assets. However, it appears that they can sometimes stray far away from that. For example, take PZA on November 20th and the 21st. Its IV had a 15% swing down, but the actual NAV and price of the ETF had very little change. I called Powershares and they seemed to half-agree with me that IV doesn't mean anything in a volatile market, but they still weren't clear. They say the IV and NAV are calculated the same way, but this is impossible given the widely divergent values of the IV and NAV shown lately. Does anybody have any insight in to this?