This week, we present to you one of those interesting data discoveries that occasionally crops up in the course of our routine study of various technical and sentiment indicators. In the process of composing his weekly report to our research team, Schaeffer's Quantitative Analyst Chris Prybal noted an apparent correlation between CBOE Volatility Index (VIX) futures put option volume and the action in the S&P 500 Index (SPX). Namely, per the chart immediately below, it would seem that when VIX's 20-day cumulative put volume falls below 400,000 contracts, the S&P tends to experience some weakness.
While VIX 20-day put volume regularly clocked in below the 400,000 threshold prior to 2013, there have been only 10 occasions since then when this low bar has been breached (limiting the study to only one signal per month to eliminate some redundancies). Upon further inspection, these troughs in VIX put volume have, in fact, served as precursors to VIX spikes, as well as some corresponding S&P weakness.
Looking out 21 days after a low-volume signal from VIX put options, the S&P is sitting on an average loss of 0.7% -- well below its average "anytime" 21-day return of 1%. Meanwhile, the VIX is up nearly 26%, on average, 21 days post-signal -- easily outstripping its average return of 2.8% for this time frame. While average returns go on to stabilize (and eventually turn positive again) for the S&P after this initial 21-day window, VIX returns don't peak until 63 sessions following the signal, when the average return arrives at 27% (compared to VIX's average 63-day return of only 4.2%). So if this pattern repeats itself in the weeks ahead, we can expect to see a short-term downturn in the S&P, accompanied by what may be a comparatively prolonged increase in the VIX.
Meanwhile, September tends to be a rough month for stocks already. Over the past five years, the S&P has averaged a 1.2% loss in September -- the worst of all monthly returns, on this basis.
So from a pure data analysis standpoint, there seems to be legitimate cause to suspect there may be some short-term weakness in stocks on the horizon -- along with an even more pronounced surge in the VIX. And while we wouldn't recommend unloading all of your shares and heading for the bunkers on the basis of what amounts to a relative handful of data points, those who prefer to play it safe might wish to avail themselves of some portfolio protection in the form of put options -- before the price to obtain that protection jolts higher.