Large firms operating in underdeveloped institutional environments of transition economies tend to invest in seemingly unrewarded corporate social responsibility (CSR) initiatives. To explain this phenomenon, we extend the literature on the motives behind CSR disclosure in agribusiness from the institutional perspective on organizational legitimacy. The thesis is that self-interest rationales for CSR disclosure, as advocated by the strategic-legitimacy perspective, fall short of explaining the full scope of instrumental motivations for the proactive and excessive transparency initiatives of agribusiness companies. Using the example of internationally listed Ukrainian agroholdings, we show that firms faced with institutions that do not appropriately support access to market transactions not only adapt to fluctuations in the business environment but also proactively address key institutional bottlenecks by engaging in higher transparency and nonmarket initiatives. The case study analysis of the voluntary CSR disclosure of four agroholdings is conducted based on in-depth interviews with corporate managers and complemented with information from corporate reports and websites. This analysis offers insights into the development of corporate farming and its economic and social repercussions in Ukraine and, more generally, expanding the concept of CSR itself.