While research on ESG reporting recognizes the influence of legitimacy pressure, less attention has been paid to legitimacy pressure originating from internal firm attributes. We develop a framework wherein environmental reporting is viewed as a reaction to intangible resources, the value of which is susceptible to uncertainty and tension created by potential environmental concerns surrounding the firm. We apply our framework to environmental disclosures made by US-headquartered firms listed in NYSE and Nasdaq closely followed by financial analysts and disclosure content—environmental favorableness and value relevance—and find support for our framework. Our study contributes to the literature on ESG disclosure by uncovering the impact of legitimacy pressure arising from internal firm attributes and advance research on legitimacy theory by identifying a specific decoupling mechanism.