We investigate the economic consequences of the Basel III requirement to include unrealized fair value gains and losses on available-for-sale (AFS) securities in regulatory capital. Using data for U.S. banks we find negative market reactions around news indicating an increased likelihood of this regulatory change being implemented, consistent with increased regulatory costs. We also find that banks affected by this regulation reduce their investment in risky AFS securities relative to unaffected banks. This result suggests that extending the use of fair values for regulatory purposes reduces ex ante risk taking.

Exploiting detailed disclosures mandated by Accounting Standard Codification (ASC) 820, we provide evidence for the return relevance of Level 3 fair value remeasurements for a comprehensive sample of U.S. listed banks. We find that Level 3 remeasurements recognized in earnings are more return relevant than those recognized in other comprehensive income (OCI). Our results suggest that Level 3 remeasurements in OCI partially reflect transitory illiquidity discounts that are less relevant when banks have the ability to hold the underlying assets. The regulatory capital treatment of OCI also affects the return relevance of Level 3 remeasurements in OCI. Importantly, we find no differences in the return relevance of realized versus unrealized Level 3 remeasurements in earnings, allaying concerns that investors perceive unrealized Level 3 remeasurements of lesser quality. Overall, our findings support the usefulness of the segregated disclosures of Level 3 fair value remeasurements. Data Availability: Data are available from the public sources cited in the text.