I am trying to properly calculate the delta, vega and theta for an options strategy that involves buying a 90 day ATM SPX put and selling a 90 day ATM VIX call.
Here is what I have done so far:
- SPX = 5600
- VIX = 16
- SPX put Delta = -0.5
- VIX call Delta = 0.5
- VIX/SPX Beta = -5.42
- SPX put Vega = 11.9
- VIX call Vega = 0.038
- SPX put Theta = -1.17
- VIX call Theta = -0.012
- The Beta is from 1 year historical daily return data.
- Combined Delta = (-0.5) - (-5.42 x 0.5) = 2.21
- Combined Vega to SPX = (11.9) - (0.5) = 11.4
- Combined Theta = (-1.17) - (-0.012) = -1.16
Perhaps this is correct but I am doubtful because its long the SPX but somehow also long volatility which makes no sense.