Maybe I should have read the CBOE whitepaper but I never did... Now I cannot find it.
I was looking at SPY/SPX just a moment ago and noticed that spot VIX doesn't match with SPY or SPX IV. Why not? I always thought that is what VIX was.
I can see current spot VIX at 10.71 at the moment while SPY/SPX IV is at 8.4%
EDIT!! this is just further info based on accepted answer.
SPY option chains look like someone thinking the world is gonna end.