Option Replication With Large Transactions Costs

Abstract

Contrary to a continuous-time model, in a discrete-time binomial model it is possible to construct a self-financing strategy which exactly replicates the payoff of a European option contract at maturity in the presence of proportional transactions costs. We derive an upper boundary for the cost factor in a market where all investors face the same factor. This upper boundary ensures the efficiency of the riskfree bond price as well as the stock price process. It turns out that perfect replication is optimal in the presence of only one transactions costs factor. Furthermore, conditions are given under which superreplicating strategies are dominant under differential transactions costs. A closed-form solution for the value of a Short call option is derived. While this least initial endowment is preference-free, the individual replicating strategy is preference-dependent. In addition, we show how the value of a Long European call option is derived computationally easily.