This paper examines risk-taking incentives in banks under different accounting
regimes with capital regulation. In the model the bank's decisions of capital issuance
and investment policy are jointly determined. Given exogenous minimum capital requirement, the bank is more likely to issue equity capital in excess of the minimum
required level and implement less risky investment policy under either lower-of-cost-or-
market accounting or fair value accounting than under historical cost accounting. But
fair value accounting may induce more risk-taking compared to lower-of-cost-or-market
accounting due to short term interest in the part of the bank. However, the disciplining role of lower-of-cost-or-market accounting may discourage bank's incentive to exert
project discovery effort ex-ante if the ex-ante effort plays an important role. From the
regulator's perspective, the optimal accounting choice will be governed by a tradeoff
between the social cost of capital regulation and the efficiency of the bank's project
discovery efforts. When the former effect dominates, the regulator prefers lower-of-
cost-or-market accounting; when the later effect dominates, the regulator may prefer
other regimes.