Recent studies on competition law and digital markets reveal that accumulating personal information through data collection and acquisition methods benefits consumers considerably. Free of charge, fast and personalised services and products are offered to consumers online. Collected data is now an indispensable part of online businesses to the point that a new economy, a data-driven sector, has emerged. Many markets such as the social network, search engine, online advertising and e-commerce are regarded as data-driven markets in which the utilisation of Big Data is a requisite for the success of operations. However, the accumulation and use of data brings competition law concerns as they contribute to market power in the online world, resulting in a few technology giants gaining unprecedented market power due to the Big Data accumulation, indirect network effects and the creation of online ecosystems. As technology giants have billions of consumers worldwide, data-driven markets are truly global. In these data-driven markets, technology giants abuse their dominant positions, but existing competition law tools seem ineffective in addressing market power and assessing abusive behaviour related to Big Data. This book argues that a novel approach to the data-driven sector must be developed through the application of competition law rules to address this. It argues that current and potential conflicts can be mitigated by extending the competition law assessment beyond the current competition law tools to offer a modernised and unified approach to the Big Data–related competition issues. Promoting new legal tests for addressing the market power of technology giants and assessing abusive behaviour in data-driven markets, this book advocates for cooperation between competition and data protection authorities. It will be of interest to students, academics and practitioners with an interest in competition law and data protection.