The purpose of this paper is to study the mimetic isomorphism process among firms in a context of expectations of further non-financial disclosure regulation. From the new institutionalism theory approach, we study the effect that the 2014/95/EU Directive transposition into the Spanish law had on 120 companies over an eight-year period and the isomorphism determined by their activity and leadership in reporting before (expectations period) and after the law enactment. Before the law, a trend to increase disclosure was observed, especially among environmentally sensible sectors and low-level reporting firms, while afterwards, the trend was reversed except for leading companies, highlighting the prevalence of the mimetic and normative isomorphism. This work deepens understanding of the adoption processes of coercive norms based on mimetic behaviors and coercive isomorphisms and helps in predicting the effect of a given norm after its announcement and approval, supporting more efficient designs for future legislation
