There is huge open interest on the Aug 220 strike in SPY,
The SPX is at an all time high, yet vol in the SPX has stopped dropping. If anything it might have crept higher.
If you haven't figured it out yet, when the SPX takes a dive the high ups at CBOE think $$$$. Well, take a look at the price of options in CBOE they are cheap
After being up nicely then giving it away OIV and OVX are now at 3 month highs, although no where NEAR where they got to in January