Respuesta :
Answer:
you should hold 76 shares of stock per 100 put options to hedge your risk.
Explanation:
Current stock price, S = $85
Risk-free rate of return, r = 5%
Standard Deviation, v = 25%
Exercise price, X = $90
expiration date, t (in years) = 30 days = 1 month = 1/12 = 0.083333 years
The option price (OP) is given by the formula:
[tex]OP = Xe^{-rt} * N(-d_{2} ) - S*N(-d_1)[/tex]
[tex]d_1 = [ln(S/X) + (r + v^{2} /2)t]/vt^{0.5}\\d_1 = [ln(85/90) + (0.05 + 0.25^{2} /2)*0.08333]/(0.25*0.08333^{0.5})\\d_1 = -0.6982[/tex]
[tex]d_2 = d_1 - (vt^{0.5})\\d_2 = -0.6982 - (0.25*0.08333^{0.5})\\d_2 = -0.7704[/tex]
Using the pro-metric calculator for the cumulative normal distribution:
N(-d1) = N(- (-0.6982)) = N(0.6982) = 0.75747
N(-d2) = N(-(-0.7704)) = N(0.7704) = 0.77947
[tex]OP = Xe^{-rt} * N(-d_{2} ) - S*N(-d_1)[/tex]
[tex]OP =[ 90e^{(-0.05*0.08333)} * 0.77947] - (85*0.75747)\\OP = 5.48[/tex]
Note that N(-d₁) = 0.76
This means that 76/100 (i.e to hedge your risk, you should hold 76 per 100 put options )