Quote from jb514:
Excuse my ignorance, but please elaborate on this.
Well, I am saying that supply/demand curve for implied volatility is not as elastic with respect to actual realized vol as one would expect. Thats what the risk premium is all about.
Quote from spindr0:
OK, I get the negative expectancy due to slippage and commissions. But what about diagonalized positions where you're selling volatility (sell near month high IV and buy lower IV of further month)? Isn't it possible for such animals to have positive expectancy?
Technically speaking, in an efficient market no derivative trade could have any positive expectancy. So, no matter what combination you would come up with, it would not have positive expectation.
Quote from jb514:
Does the IV really change based on expiration?
Of course it does, depending on the environment, front vol could be significantly different from the back vol. There are, again, a lot of good reasons for it. Term structure of vol, both in terms of time (different vol for different expiries) and in terms of the strikes is a pretty fascinating thing in it's own rite.
Quote from jb514:
I think in order to optimize you would need to sell the current month and buy the next month once after the volatility crush.
Well, in the example described you are selling gamma (convexity at the very front) and hoping to protect yourself with cheaper Vega. So, if the realized volatility comes, you would hope that longer dated implied will increase in some proportionate manner and you would be able to alleviate some of your losses. You don't want to be naked short gamma in a crash, you want to be hedged in some way.
In any case, I am going to sleep so we can continue this tomorrow, God willing.