CF chapter 21 Flashcards
Binomial model (option pricing)
Stock price follows a ‘binomial tree’ with a given number of periods
In every period the stock price may either go up or down by a known amount or percentage
The one-period risk-free interest rate is given
Delta
Number of shares purchasedB
B
Initial investment in bonds
Binomial pricing formula stock goes up
Su +(1+rf)*B = Cu
Cu = call price up
Su = stock price up
Binomial pricing formula stock goes down
Sd + (1+rf)*B = Cd
Sd = stock price down
Cu = call price down
Delta formula
Cu - Cd /Su - Sd
or
-[N(-d1)]
B formula
Cd - SD * delta / 1+ rf
or
PV(K)∙[N(-d2)]
Option price in the binomial model
C = S *D + B
Black sholes model formula
C = S*N(d1) −PV(K)∙N(d2)
d(1) formula
ln(S/PV(K))/(omegasqr(T) + omegasqr(T)/2
d(2) formula
1-omega*sqr(T)
Black-Scholes Price of a European Put Option on a Non-Dividend-Paying Stock
P = PV(K )[1 - N(d2 )] - S[1 - N(d1)]
P (risk free probabilitiess p and 1-p)
P = (1+rf)*S -Sd/Su - Sd