The Strategic Under-Reporting of Bank Risk

Abstract

We show that banks significantly under-report the risk in their trading book when they have lower equity capital. Specifically, a decrease in a bank's equity capital results in substantially more violations of its self-reported risk levels in the following quarter. The under-reporting is especially high during the critical periods of high systemic risk and for banks with larger trading operations. We exploit a discontinuity in the expected benefit of under-reporting present in Basel regulations to provide further support for a causal link between capital-saving incentives and under-reporting. Overall, we show that banks' self-reported risk measures become least informative precisely when they matter the most.

Keywords: value-at-risk, risk-based capital requirements, risk measurement, systemic risk

JEL Classification: G20, G30