Various studies have highlighted the considerable regulatory influence of the European Union (EU) on digital platform (DP) firms. However, the role of stakeholders in individual competition cases remains underexplored. To fill this gap, this article draws on the conceptual framework of Market Power Europe and contends that the main sources of the European Commission's influence in this field are not only the EU's market size and regulatory capacity but also relevant market information provided by stakeholders such as consumer groups, business associations, and the target firm's competitors. Market information helps the Commission alleviate the problem of information asymmetry and effectively regulate complex and fast‐moving areas such as DP markets. A close analysis of three Google antitrust cases concluded between 2017 and 2019 provides initial empirical evidence supporting this conclusion. Overall, this study contributes to the literature on EU competition policy and greater understanding of the global political economy in relation to DP firms.