Guo and Zhu (2017) recently proposed an equal-risk pricing approach to the valuation of contingent claims when short selling is completely banned and two elegant pricing formulae are derived in some special cases. In this paper, we establish a unified framework for this new pricing approach so that its range of application can be significantly expanded. The main contribution of our framework is that it not only recovers the analytical pricing formula derived by Guo and Zhu (2017) when the payoff is monotonic, but also numerically produces equal-risk prices for contingent claims with non-monotonic payoffs, a task which has not been accomplished before. Furthermore, we demonstrate how a short selling ban affects the valuation of contingent claims by comparing equal-risk prices with Black-Scholes prices.
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