This article considers the pricing and hedging of barrier options in a mark
et in which call options are liquidly traded and can be used as hedging ins
truments. This use of call options means that market preferences and belief
s about the future behavior of the underlying assets are in some sense inco
rporated into the hedge and do not need to be specified exogenously. Thus w
e are able to find prices for exotic derivatives which are independent of a
ny model for the underlying asset. For example we do not need to assume tha
t the underlying assets follow an exponential Brownian motion.
We find model-independent upper and lower bounds on the prices of knock-in
and knock-out puts and calls. If the market prices the barrier options outs
ide these limits then we give simple strategies for generating profits at z
ero risk. Examples illustrate that the bounds we give can be fairly tight.