One of the persistent characteristics of the CBOE‘s VIX index is the Christmas Effect—the tendency for VIX to drop down to relatively low levels during the Christmas holidays. The CBOE’s VIX volatility futures predict this drop for months in advance, and it has come to pass again this year. I am aware of at least three possible explanations for this:
- Option market makers and others short options reduce their prices before the holidays so that they don’t get stuck with time decay (theta) during the multiple days off
- Traders in general go on vacation the end of December, volume drops, and the market becomes lethargic, reducing volatility
- People expect volatility to decrease, trade accordingly, and it becomes a self fulfilling prophecy
I am skeptical about calendar based trading strategies (e.g., The S&P was up 8.5% this October), but this effect has been persistent, perhaps because it is not as easy to profit from it. The VIX index itself is not investable, and not many people are comfortable investing in VIX futures.
I was curious how the VIX behaved over the last few years in December and January, so I generated the chart below using VIX historical data from the CBOE.
To make the chart more readable I did a linear interpolation over weekends / holidays and used a 3 day moving average. Although 2008 shows the Christmas effect, the market that year was clearly in an unusual state, so I have excluded it from the follow-on charts. This next chart zooms in on the more normal years.
There does seem to be a fairly consistent low around the 23rd of December, but what jumps out is the big uptick in volatility in the second half of January. Only 2006 seems to have skipped this. As I mentioned before, the VIX index is not directly investible—but the CBOE’s VIX futures are. I used my VIX futures master spreadsheet (http://tinyurl.com/8xwypqc) to generate the chart below showing the behavior of the front month VIX futures, the next ones to expire.
With the VIX futures the December dip comes a few days earlier, but the January upswing starts at about the same time.
In my experience the future is often uncooperative in repeating the past, but this VIX Yet to Come, looks like a reasonable bet.

















