We use a model of mean-shifting investment technologies to study the relationship between market structure, risk taking and social welfare in lending markets. Introduction of loan market competition is shown to reduce lending rates and to generate higher investments without increasing the equilibrium bankruptcy risk of borrowers. Hence, there need not be a tradeoff between lending market competition and financial fragility. Such a tradeoff may not emerge either when banks compete by conditioning interest rates on investment volumes irrespectively of whether credit rationing takes place or not.

We characterize the profit-maximizing reserves of a commercial bank, and the generated probability of a liquidity crisis, as a function of the penalty imposed by the Central Bank, the probability of depositors' liquidity needs, and the return on outside investment opportunities. We demonstrate that banks do not fully internalize the social cost associated with the bail-out policy if the liquidity needs of individuals are correlated, and that competitive interbank markets will induce banks to raise their reserves under reasonable conditions. The marginal benefits from an interbank market decrease as the correlation between the liquidity shocks of banks increases.

Deposit insurance designs in many countries place a limit on the coverage of deposits in each bank. However, no limits are placed on the number of accounts held with different banks. Therefore, under limited deposit insurance, some consumers open accounts with different banks to achieve higher or full deposit insurance coverage. We compare three regimes of deposit insurance: no deposit insurance, unlimited deposit insurance, and limited deposit insurance. We show that limited deposit insurance weakens competition among banks and reduces total welfare relative to no or unlimited deposit insurance.