Enhancing consumer welfare is at the heart of competition law. Of the many facets that can be considered as consumer welfare, changes in price and output are the easiest to measure and have, therefore, traditionally been the de facto benchmark for assessing anticompetitiveness. There are two current trends disrupting this: first, a debate as to whether other elements of consumer welfare should play a greater role, particularly treatment of customers’ data; and second, the importance of big data in maintaining competitive markets. These trends are reflected in the growing regulatory scrutiny of big tech firms, the focus of antitrust regulators on the digital economy and, in the European Union in particular, the May 2018 implementation of the General Data Protection Regulation (GDPR). This chapter provides an overview of the current activities of the EU and US regulators in cases at the intersection of competition law and data issues. Many of the developments can be seen in the regulators’ enforcement of the merger control laws, but there have also been significant developments in the antitrust arena more broadly.