Where does Information Processing in a Fragmented Market Take Place? – Evidence from the Swiss Stock Market after MiFID

The implementation of MiFID lead to fragmentation of trading in European equities. We analyze information processing for a sample of Swiss stocks on the Swiss exchange and on Chi-X, the largest multilateral trading facility. According to Hasbrouck information shares, the determination of a leading market is not conclusively possible. By applying an autoregressive conditional intensity (ACI) model that explicitly takes the asynchronous structure of order arrivals into account, we find strong evidence that Chi-X is the leading market in terms of intensity based information shares.