["Corporate Social Responsibility and Environmental Management, EarlyView. ", "\nABSTRACT\nThe year 2025 marked an important phase in the implementation of the Corporate Sustainability Reporting Directive (CSRD) with companies of a certain size in the European Union (EU) being obliged to report for the first time under CSRD rules. Following entry into force of the CSRD in January 2023, companies faced a complex set of rules and standards for their sustainability reporting practices. With the practicalities of sustainability reporting subject to the CSRD, the EU as an institutional actor is not only changing reporting rules but also delivering benefits and creating challenges, uncertainties, and certainties in companies as institutional actors. Bringing together the EU's political ambitions for sustainability reporting in connection with the European Commission's Sustainable Finance Action Plan, the European Green Deal, and the ambitions of companies to conduct profitable and sustainable business, this study argues that the EU is not only enforcing institutional change but also significantly altering the institutional environment in which companies operate. The findings of our interview‐based case study highlight the impact of the CSRD as a regulative element on normative and cultural‐cognitive factors in this enforced institutional change. The respondents include Finnish companies subject to CSRD reporting from financial years 2024 and 2025 and professionals in administrative and advisory roles in Finland and the EU. This study contributes to sustainability research by examining the perceived consequences of a significant change in the institutional environment in which EU companies operate.\n"]