Equity volatility is at its lowest levels since the VIX was
first calculated. Since 1990, 26 days have seen the VIX close below 10. Seventeen of
those days have been this year, and 10 have been in the last month. One trivial reason
for the persistently low VIX is that realized volatility has been even lower.
Since the start of July the average VIX level has been 10.26 but close to close
realized S&P volatility has been even lower at 5.9%.
This is obvious, but also means that the “option markets are
complacent about risk” argument doesn’t hold water. The actual market isn’t
moving so no one is going to pay a lot for S&P options or VIX futures in
this environment. The real question is, “why isn’t the market moving?”
Prices and volatility are the aggregate of market
participants views. If all investors have the opinion that volatility will be
large then it will be. But another way volatility can come about is if all the
traders have different views of future returns. Here is a very simple example.
Think of a market with two traders. They both think volatility will be 30%, but
one thinks the return will be 10% and the other thinks it will be 30%. The
average of these two opinions will have a volatility of 40%, higher than
either’s view of market risk. This is because the total
variance is the average variance plus the average squared mean minus the square
of the average mean.
This effect is shown in Figure One:
Figure One: A mixture of normal distributions (grey)
has a higher variance than the components(blue and orange).
So it is entirely possible that the current low
volatility is the result of converging return estimates rather than any concept
of lower intrinsic risk. This seems like a tough hypothesis to test, but also
give a possible counterpoint to the idea that traders have a lowered
expectation of risk.
Euan, can that be relevant in options though because the 'mean expectation' should be the same for both traders shouldn't it given it the option vol is determined under risk-neutral?
ReplyDeleteNice explanation, thank you.
ReplyDeleteRobert, that is a good question. Once we go to the risk neutral distribution it is true that drift no longer plays a part. But this effect is also in the underlying and that vol feeds through into the implied.
ReplyDeleteThat is very true. Hard to disentangle. We had a go in a different context a few years ago, related example here:
ReplyDeletehttp://www.bankofengland.co.uk/publications/Documents/quarterlybulletin/qb040205.pdf
Cheers, enjoying the blog.