Quote from dmo:
This is not an arb because buying VIX futures only covers part of your risk. When you short options you assume vega risk and gamma risk. Buying VIX futures only covers your vega risk. You're still naked short gammas.
Right, need to hedge gamma as well, I'm assuming it's part of the option trade already, just thinking if the seller can add VIX future buying to take advantage of cash/future divergence, it makes sense to me
Right. And note that most of the time when the VIX trades around 20, the futures do not trade at a discount to cash. For the past several months in fact, the futures have traded at a premium to cash. [/QUOTE]
We can make a strategy to trade VIX divergence, when the futures trade at a discount to cash, long VIX future and short SPY premium (long fly is probably better than short straddle since it's defined risk). When the futures at a premium to cash, reverse the trade, ...