Résumé en anglais

This empirical study based on data from several exchanges and trading platforms for a sample of 153 European blue chip stocks over a post-MiFID three-month period shows that the way liquidity correlates with fragmentation is diverse and depends on the market, the type of liquidity metrics, and the type of fragmentation that is considered. All in all, fragmentation seems to be more beneficial to global traders trading in several market places than to local traders trading on the primary exchange only, which confirms the crucial role of order routing systems in fragmented markets. Further, fragmentation adversely affects price quality by increasing short-term volatility. That adverse effect is assignable to market-traded order flow fragmentation but not to internalization.