问题如下：
A volatility trader observes that the VIX term structure is upward sloping. In particular, the VIX is at 13.50, the front-month futures contract trades at 14.10, and the second-month futures contract trades at 15.40. Assuming the shape of the VIX term structure will remain constant over the next three-month period, the trader decides to implement a trade that would profit from the VIX carry roll down. She will most likely purchase the:
选项：
A. VIX and sell the VIX second- month futures.
B. VIX and sell the VIX front- month futures.
C. VIX front- month futures and sell the VIX second- month futures.
解释：
C is correct.
VIX futures converge to the spot VIX as expiration approaches, and the two must be equal at expiration. When the VIX futures curve is in contango and assuming volatility remains stable, the VIX futures will get “pulled” closer to the spot VIX, and they will decrease in price as they approach expiration. Traders calculate the difference between the front-month VIX futures price and the VIX as 0.60, and the spread between the front-month and the second-month futures is 1.30. Assuming that the spread declines linearly until settlement, the trader would realize roll-down gains as the spread decreases from 1.30 to 0.60 as the front-month futures approaches its expiration. At expiration, VIX futures are equal to the VIX, and the spread with the old second-month (and now the front- month) futures contract will be 0.60. Finally, since one cannot directly invest in the VIX, trades focusing on the VIX term structure must be implemented using either VIX futures or VIX options, so Answers A and B are not feasible.
请问如果将C选项修改一下，改为仅short two month的VIX futures，那么这个选项是对的吗？ 我的问题主要在于为什么既要long 近月合约，又要short远月合约，仅short 2 month的这样不是综合的回报更高吗？谢谢！