Put-call parity and the informational efficiency of the German DAX-index options market

Using transaction data for options on the German stock index (DAX), we examine the informational efficiency of this relatively new options market. Because DAX options are European style and the underlying index is a performance index, we avoid problems due to dividend estimation and the assessment of the early-exercise effect, which are encountered in existing studies. Ex-post and ex-ante tests are carried out to simulate trading strategies for exploiting put-call parity violations. We find that ex-post profits diminish dramatically when the implementation of the arbitrage strategies is delayed and/or after transaction costs are accounted for. In general, however, arbitrage restrictions, which rely on short selling of the component stocks of the index, tend to be violated more severely than those relying on long positions in these stocks. Given the short-selling restrictions in Germany, these apparent arbitrage opportunities cannot be easily exploited in practice. Furthermore, the results for different subsamples suggest that traders were subject to a learning process in pricing these relatively new instruments.