'Correlation Spasm' - VIX Surges By Most In 10 Months After OpEx

As we detailed earlier, today's options monthly expiration is of decent size, but far less notionally than that of a quarterly expiration like last June, or the upcoming Sep expiration.

However, while the index expiration doesn't appear to be all that large, this heavily-concentrated market can be swung by expiration-mechanics of large single stocks.