This chapter structures the background of inquiry into transparency and accountability in the financial sector is substantiated through an explanation of the interdisciplinary links between banking regulation and practice. In terms of regulatory focus, market efficiency and prudence are two important concerns in the context of financial markets and participants. Regarding market efficiency, market liquidity and information availability are important issues for regulators to consider. In the context of financial markets, transparency may provide the individual merit of promoting market efficiency under certain conditions, although it is generally better understood as a tool for accountability. EU policymakers had long considered how best to enhance market efficiency, and in 1993, they formally adopted the Investment Services Directive of 1993. During the 1980s, regulators were also focused on capital adequacy and the organizational resilience of banks. An important area where regulatory focus on transparency and accountability has risen is the area of internal control and governance within financial institutions.