Today’s the one-week anniversary of the largest VIX spike on record. How are you celebrating?

This time last week, traders and market participants were busy marveling at the biggest intraday jump on Wall Street’s “fear gauge” in the (relatively short) history of the series.

Not that anyone needs a visual reminder, but just in case:

That’s a 42-vol surge. It was, in a word, hilarious.

But not everyone thought it was funny. Folks like Larry Summers suggested it needs to be investigated. By a special counsel maybe. Maybe we need congressional hearings. If anything calls for an inquisition, surely it’s an anomalous spike on a measure of implied equity volatility. Can you imagine what kind of circus that would be? Marjorie Taylor Greene interrogating a Cboe official.

Anyway, Summers’s concerns center around the (self-evident) contention that what happened pre-cash equities open on August 5 had quite a lot to do with liquidity or, more to the point, an acute lack thereof. If you’re curious as to what that looks like, feast your eyes:

That’s “six hours of dislocation,” as SocGen’s equities vol team put it. (Note: The figures use an indicative bid-ask for the VIX.)

“The pre-market open period on August 5 stands out in terms of illiquidity,” the bank’s Jitesh Kumar remarked, adding that although things have “largely normalized,” the situation’s still a bit touch and go.