March 21st, 2004, 5:11 pm
Help!! I am at a loss on how to do thisQuestion : Option Pricing and Integration Consider a basic European Barrier Knock Up and In Call, whose price is given by the expectation call = exp ^(-rT) E[0,ST -K]+ for all ST >BWherer = local interest rateST = price at maturity time TK = strike price B = barrier Note B > K Derive the formula for pricing this option starting from standard geometric Brownian motion formula given below.ST =S0 exp{(r-g- (v^2)/2)T + vW(T)}Whereg = foreign interest rate or dividend rateT = maturity timeS0 = spot price at t=0 v = volatility W(T) = Wiener process = Z(T^1/2) and Z = N(0,1)Hints: · We are interested in the case where S(T) = B· Solve for this special barrier case in terms of Z, use this later on after the integration is solved· Split the expectation (S-K) into integrals S and K. · Solve each integral – easiest way is arrange each integral such that the subject of the integral is in the form of the standard marginal normal distribution. Then you can assume the integral of the marginal distribution is equation to the cumulative distribution. You will have to make use of the sum of squares property to do this.· Once the integral is solved then substitute in the special case for Z· Subtract Integral 2 form 1 to get the final formula, remember to discount the integral or expectationHelpful references: Zhang – Exotic OptionsExotic options : a guide to second generation options / Peter G. Zhang.