18.IV.1.1.1 Advantages of the ISD approach

During the ISD timeframe, within the vast majority of Member States RMs, as well as some alternative trading systems, published a high amount and timely equity pre- and post-trade data. The high amount and timely data was the result of national law requiring the publication of such data or rulebooks of RMs and alternative trading systems, as approved under national law.1 The concentration of trading on one or a few RMs was the consequence of the optional ISD concentration-rule, as well as national law providing advantages (e.g. beneficial fiscal treatment) in case orders were sent to RMs.2