Some Thoughtful Points on the VIX

Larry Summers via Tyler Cowen:

SUMMERS: Second, the VIX — people tend to underappreciate this. The volatility of the market moves very much with the level of the market. The reason is that if a company has $100 of debt and $100 of equity, and then the stock market goes up, it’s 50/50 levered.

If the stock market goes up by $100, then it has $100 of debt and $200 of equity and it’s only one-third levered. So when the stock market goes up, its volatility naturally goes down. And the stock market has gone way up over the last 10 months. That’s a factor operating to make its volatility go significantly down.

It’s also the case if you look at surprises. The magnitude of errors in the consensus estimates of company profits or the consensus estimates of industrial production or what have you, numbers have been coming in close to consensus to an unusual degree over the last few months.

I think all those things contribute to the relatively low level of the VIX, but those are more in the way of ex post explanations. If you had told me everything that was going on in the world and asked me to guess where the VIX would be, I would expect it to have been a little higher than it is right now.