After a strong 2013, the US equity market took a dive in January 2014 and dropped more than 3%. Is it a temporary market correction or something more substantial? Everyone has his own answer. Regardless of your outlook of the market, January has reminded us that market volatility is still one of the major risks that investors have to take care of.
To directly hedge against equity market risk, investors traditionally buy put options to protect their downside. In recent years, more and more investors include VIX derivatives in their portfolio to manage their market risk, including VIX futures, options, exchange traded products and other OTC products. The main benefits of using VIX derivatives are: 1) VIX is negatively correlated (~ -77%) with the S&P 500 Index historically, and 2) this negative correlation is convex, meaning that VIX shows more reaction to large decrease in the equity market than to market increases. Exhibit 1 shows that rises of the S&P 500 VIX Short-Term Futures Index were usually higher than the losses of the equity market when the market was in stress.
Isn’t convexity a nice feature of VIX futures? Unfortunately it is no free; VIX futures can lose money even if VIX does not change. All futures have fixed expiration days; hence the S&P 500 VIX Short-Term Futures Index has to roll from the first month futures contract to the second month futures contract prior to the expiration on the first month contract. Since Dec. 2005, for the majority of the time (~ 83%), the longer term VIX futures were more expensive than the shorter term futures and a roll cost was incurred.
This roll cost of VIX futures is equivalent to the upfront premium for equity put options. It is the price of the downside protection. The only difference is that the roll cost is distributed throughout the month as the futures price converges towards the spot while the put option premium is paid up front.
Exhibit 2 shows that the roll cost has led to significant performance drag in the S&P 500 VIX Short-Term Futures Index.