This chapter examines fund managers’ accountability as an intermediate organisational and psychological mechanism between formal performance management systems and decision-making behaviour. We challenge the simplistic ‘what you measure is what you get’ assumption underlying many applications of accountability, arguing that accountability is not merely a contractual or metric-based mechanism but involves a complex social and psychological process. Drawing on ideas from agency, stakeholder, and legitimacy theory, we analyse how formal controls, informal norms, and self-imposed standards interact in the volatile environment that makes up fund management. We explore the tensions between short-term financial targets and long-term sustainability goals, particularly under growing Environment, Social and Governance (ESG) and Sustainable Development Goals (SDG) pressures. We argue that accountability can enhance deliberation and transparency, while excessive process imposition may crowd out intuitive expertise, foster short-termism, and induce gaming behaviour. We conclude that effective accountability systems must integrate quantitative performance measures with qualitative, culturally embedded practices that support ethical reflection and balanced trade-offs between investor returns and societal value.