Arbitrage Potential in the Eurex Order Book – Evidence from the Financial Crisis in 2008

In this paper we investigate the valuation efficiency of the Eurex market for DAX single stock options. As a measure of arbitrage potential we use an adapted version of Stoll's put-call parity model. By calculating deviations from the theoretical fair put and call prices before and during the financial crisis in 2008, we find evidence for a decrease in market's valuation efficiency. Valuation efficiency is even worse for German financial stocks for which short selling was restricted. Although considerable profit opportunities are found, only a small number turn out to be profitable after transaction costs are considered. Our research complements the existing research by investigating American type stock options on a fully electronic exchange in both, volatile and stable markets