Question 42 Consider the following short put option Years to
     Question 42 Consider the following short put option: Years to expiration = 4.21 Risk-free rate = 1.54% Volatility = 95.0% Underlying asset market price Strike price = $1.00 · $13.00 · What is the Vega of this position? Please answer this question to four decimal  
  
  Solution
Vega (v) can be calculated with the help of following formula
? = S *? (T/2?) *e^-(log(S/X) + (r +?^2/2) * T) ^2 / (2?^2 *T)
OR v = S *? (d1) ? (T)
Where, ? (d1) = (e^- (d1^2/2))/?2?
And d1 = (log(S/X) + (r +?^2/2) * T) / (?*?T)
Underline asset market price (S) = $13.00
Strike price (X) = $1.00
Years to expiration (T) = 4.21 years
Risk-free rate (r) = 1.54%
Volatility (?) = 95%
Value of Pi (?) = 3.14159
Therefore,
d1 = (log ($13/$1) + (0.0154 + 0.95^2/2) *4.21)/ (0.95 *?4.21)
=2.32375
And ? (d1) = (e^-(2.32375^2/2) / (?2 *3.14159)
=0.02681
Vega (v) = $13 * 0.02681 * ? (4.21)
=0.7152
Therefore Vega (v) of this position is 0.7152.

