We provide a review of the literature surrounding institutional investor classifications, and we extend this research by examining the aforementioned classification systems and relate this to the three predominant financial systems (market-based, family-centred, and bank-centred systems). After integrating this literature we propose that future research can contribute to the corporate governance field in three main ways: through improved measurement of the central constructs, through more complex research designs (through moderated and/or longitudinal relationships), and through asking new types of questions. We suggest several questions and approaches for future research on institutional investors and their interrelationship with country financial systems.