Q. Long and short dated volatility?
1. If an investor purchase long-dated volatility as well as sells short-dated volatility then the investor is expecting a decrease in the short dated volatility and an increase in the long dated volatility.
Obviously there is no guarantee that these expectations will be realized. If short run volatility goes up or else and long run volatility decreases the pay off from the position would definitely be negative.
This is equal to an investor constructing a short straddle position by using knock-out options. Long straddle may be constructed by utilizing options which have break-out clause to put a limit to unrestricted risk of loss that arises from the short (straddle) position in the short run.
If short dated volatility turns out to be high an additional premium is able to be triggered on the options which are used for the long straddle.
This added payoff from the long volatility position off sets the losses from the short volatility position.
3. The applicable payoff function will shift upwards by the amount of the additional payoff.
4. If the added premium is a fixed amount this may cut potential losses yet it mayn't be sufficient enough. Nevertheless considering that the short position is taken for one month this risk mayn't be a very big risk.
5. It is understandable from the text that volatility positions taken by using the straddles are not pure volatility positions.