The study shows that multi-sided markets pose difficulties when the relevant product market is to be defined. These difficulties pertain to two questions. The first question is whether one or several markets should be defined. In this regard, it is not easy to extract a coherent method from the cases examined. Instead, the methods applied give the impression of ad hoc-solutions, where similar circumstances result in dissimilar outcomes. Indeed, it is hard to reconcile the different market definitions in Visa International MIF and MasterCard MIF. The uncertainties are not limited to these two cases, as the methods applied in Google Shopping too give rise to ambiguities. Why was the market for general search engine platforms separated into two distinct product markets, but the market for comparison shopping services encompassed both sides? Unfortunately, this discussion was not present in the decision. This only serves to reinforce the impression that these questions are solved on an ad hoc-basis. A clear method of approaching multi-sided markets is desirable, not least because the enforcement of competition rules must be characterized by consistency and foreseeability. Hopefully, the judgement in Google Shopping will bring further clarity to this. Nonetheless, the conclusion is that one market should be defined when differences between competitive constraints on the two sides are absent. E contrario, this means that two markets should be defined when such differences are present. This is true regardless of the market in question being a transaction or a non-transaction market. This method seems preferable to strictly adhering to the division of multi-sided markets into transaction or non-transaction markets. If the Commission’s analysis is correct in that there are no differences in competitive constraints on the two sides of comparison shopping services, in combination with crossing network effects, the platform’s multi-sidedness is a necessary trait for both sides. This means that a substitute has to be multi-sided in order for it to be included on the relevant product market, which minimizes the risk for false negatives. Vice versa, the definition of two markets allows for one-sided products to be included on the relevant product market, which minimizes the risk for false positives. This is important not only for the binary finding of dominance or non-dominance, but also the degree of dominance. As concluded above, incorrectly defining one market may artificially inflate the degree of dominance into false super-dominance, and incorrectly defining several markets may artificially dilute the degree of dominance. The second question is how substitutability should be measured. It is obvious from the cases examined that qualitative measures are used and not quantitative measures. The products’ characteristics, intended use, purpose, functionalities, users’ perceptions of the product, etc. were given much attention. The SSNIP test was not applied in any of the cases. The first conclusion to be drawn from the examination above is therefore that the difficulties regarding measuring substitutability on multi-sided markets mainly concern quantitative measures. The arguments against applying a SSNIP test related to the cellophane fallacy (in two different forms, one of which was deceivingly similar to the reverse cellophane fallacy) and differences in price sensitivities between the two sides. Network effects present an additional difficulty, which may lead to exaggerated results when measuring substitutability. The second conclusion to be drawn is that there exists a reluctance to apply a SSNIP test in a way that is tailored for multi-sided markets. One method that has been proposed is to apply the test on the total sum paid by both sides, while allowing the intermediary to adjust the increase in price in accordance with its price structure. The categorical dismissal of applying the test in this way suggests that adapted versions have some time to wait before being introduced into case law and decisional practice. If they, as their proponents argue, are a robust way of broadening the evidence of possible substitutability, this is unfortunate. The risk of defining the market overly narrow or overly broad is of course present in this regard as well. A broader spectrum of evidence therefore minimizes the risk of incorrectly finding both dominance and non-dominance.

Europe is facing a climate and environmental crisis. To respond to this, the European Commission has launched several programmes, which aim to increase sustainability and environmental protection. This aim has been condensed into the policy document that is the European Green Deal. The European Green Deal sets out the aim of making the Union’s economy climate neutral, while improving environmental protection and protecting biodiversity. To this end, several different sectors of the economy need to be overhauled.  In EU Law, a key policy area is to protect free competition. Article 101 TFEU sets out that agreements between undertakings which have as their object or effect the prevention, restriction or distortion of competition are prohibited. Similarly, Article 102 TFEU prohibits abuse by an undertaking of a dominant position.  This thesis explores what happens when competition law thus intersects with the environmental policy of the Union. The thesis identifies two main situations  of interaction. Undertakings can invoke environmental protection to justify a restriction of competition. The Union may also rely on its antitrust provisions to enforce sustainability by holding unsustainable practices as restrictive agreements or abuses of dominant behaviour, respectively, and thus prohibited by the antitrust provisions.  Generally, the thesis concludes that there is not enough information on how the Commission and the CJEU will approach arguments relating to sustainability in its antitrust assessment. The Commission’s consumer welfare standard appears to limit environmental integration to points where a certain factor results affects the environment or sustainability on the one hand, and consumer welfare on the other. The lack of information, moreover, is in itself an issue as undertakings may abstain from environmental action if they believe they will come under scrutiny due to violations of the antitrust provisions. Therefore, a key conclusion in the thesis is that the Commission and the CJEU should set out clear guidelines for environmental action by undertakings, in relation to the antitrust provisions. Similarly, the Commission appears to be cautious to use antitrust as a tool against unsustainable practices. The Commission has, however, recently decided to open an investigation into agreements which limit sustainability, which shows that the picture may be changing.

Competition and data protection law are two powerful regimes simultaneously shaping the use of digital information, which has given rise to new interactions between these areas of law. While most views on this intersection emphasize that competition and data protection law must work together, nascent developments indicate that these legal regimes may sometimes conflict.  In the first place, firms faced with antitrust allegations are to an increasing extent invoking the need to protect the privacy of their users to justify their impugned conduct. Here, the conduct could either be prohibited by competition law despite of data protection or justified under competition law because of data protection. In the EU, no such justification attempt has reached court-stage, and it remains unclear how an enforcer ought to deal with such a claim. In the second place, competition law can mandate a firm to provide access to commercially valuable personal data to its rivals under a competition law remedy. Where that is the case, the question arising in this connection is whether an enforcer can and should design the remedy in a way that aligns with data protection law. If so, the issue remains of how that ought to be done. The task of the thesis has been to explore these issues, legally, economically, and coherently.  The thesis has rendered four main conclusions. First, data protection has a justified role in EU competition law in two ways. On the one hand, enhanced data protection can increase the quality of a service and may thus be factored in the competitive analysis as a dimension of quality. On the other, data protection as a human right must be guaranteed in the application of competition law. Second, these perspectives can be squared with the criteria for justifying competition breaches, in that data protection can be invoked to exculpate a firm from antitrust allegations. Third, in that context, the human rights dimension of data protection may entail that the enforcer must consider data protection even if it is not invoked. However, allowing data protection interests to override competition law in this manner is relatively inefficient as it may lead to less innovation, higher costs, and lower revenues. Fourth, the profound importance of data protection in the EU necessarily means that enforcers should accommodate data protection interests in designing competition law remedies which mandate access to personal data. This may be done in several ways, including requirements to anonymize data before providing access, or to oblige the firm to be compliant with data protection law in the process of providing access. The analysis largely confirms that anonymization is the preferable option.