Abstract Sustainability reporting is a key tool for managing uncertainty because it provides transparency, accountability and reliable information on companies' environmental, social and governance (ESG) performance. By disclosing relevant data and insights, sustainability reports enable stakeholders to make informed decisions, understand companies' environmental and social impacts, and assess their long-term sustainability strategies. This paper examines the evolving landscape of corporate sustainability reporting in Bulgaria, taking into account the broader context of corporate impact assessment and impact accounting. The study begins with an introduction to the growing importance of sustainability reporting in today's business environment, emphasising the need for transparency, accountability and compliance. A review of the current literature on the subject reveals a notable trend towards increased disclosure of environmental initiatives and impacts, alongside persistent challenges such as inadequate quality and quantity of reporting, expertise gaps and inconsistencies in guidance. To address these issues, the research uses a mixed-methods approach to explore the nature of sustainability reporting, regulatory frameworks and accountability practices in Bulgarian companies. Through data analysis and interpretation of findings, the study reveals a positive trend towards greater disclosure of sustainability initiatives and impacts, albeit with significant variations in reporting quality and methodology. As Bulgarian companies prepare for the implementation of the Corporate Sustainable Reporting Directive (CSRD), the study highlights the essential need to align with evolving sustainability reporting standards to promote transparency and accountability. By addressing these challenges, companies can better meet stakeholder expectations, contribute to sustainable development goals, and build reputation and trust in the corporate sector. Finally, this paper contributes to the field of sustainability reporting by providing valuable insights into the current state of affairs in Bulgarian companies.