
242 INTERNATIONAL FINANCIAL MANAGEMENT
If the spot rate at expiration is greater than the strike rate, Portfolios I and II would pay
off the same amount—the spot rate of the foreign currency. If the spot rate is less than or
equaltothestrikerate,PortfolioIhasalargerpayoffthanPortfolioII.Topreventarbitrage,
Portfolio I will be priced to sell for at least as much as Portfolio II. This leads to the following
lower bound on the value of the European call option:
c
S
r
K
r
e
T
≥ Max
()
,
11
0
+
−
+
Similarly, for a European put option, the lower bound on the values is
P
K
r
S
r
e
h
T
f
Max
()
,
11
0
As in the case of a call option, t ...