In absence of deposit insurance, underdeveloped financial systems can exhibit a coordination failure between banks, unable to commit on safe asset holding, and depositors, anticipating low deposit repayment in bad states. This paper shows conditions under which a government can solve this failure by imposing safe asset purchases, which boosts deposits by increasing depositor repayment in bad states. In so doing, financial regulation stimulates bank profits if subsequent deposit growth exceeds the intermediation margin decline. As a result, it also promotes loans and branch installation with deposits. Two empirical tests are presented: 1) a regulation change by the National Bank of Ethiopia in 2011; 2) the introduction of bank taxes in Antebellum USA (1800-1861). Analyzing bank balance sheets and long-term branch installation, the regulation effects are isolated exploiting heterogeneity in bank size and policies introduction respectively, and find increases in branches, deposits, loans, and safe assets, with no decline in overall profits.