14.I Introduction

The price of equity pre- and post-trade data is an important aspect of whether or not an equity market is transparent in practice. Even where sufficient, reliable, and timely equity pre- and post-trade data is published and consolidated, too high prices for the equity pre- and post-trade data would reduce the actual access to the data, for example, because the expensive data can only be licensed1 by larger and more sophisticated investors (not: retail). Access to equity pre- and post-trade data has become increasingly important for the EU equity markets in the past decades. Demand for equity pre- and post-trade data has grown due to technological development (in particular algorithmic trading) and increased competition in the EU equity markets (i.e. a wider choice of trading platforms).2 ‘Reasonable’ equity pre- and post-trade data prices and data users knowing what they are paying is in effect becoming increasingly important.3 As will be shown in this part of the research (Part IV), the latter is visible from the ISD to MiFID II. A substantial increase in EU regulation for equity pre- and post-trade data prices is visible. But before examining the regulatory regimes of the ISD, MiFID I, and MiFID II (Chapters 15-17), a conceptual framework of equity pre- and post-trade data prices is provided in this chapter. The conceptual framework provides the context of the increase in EU regulation for equity pre- and post-trade data prices. The main concepts are examined below.