The aim of this doctoral thesis is to advance understanding of the interrelationships between equity markets and firm innovation in their institutional context. The principal theoretical issue addressed in this thesis is reflected by the main research question, "How and why do equity markets and firm innovation interact?" Herein, the aim is to identify generative mechanisms that underlie social processes in the complex interaction between equity markets and firm innovation. In this respect, the study aims to enhance the understanding of distinct social actors'' behavior. In particular, it aims to elucidate how this behavior guides the expectations and actions of the social actors, and how these expectations and actions impact the firm innovation process and subsequent institutional change.