We propose a simple model of the sovereign-bank diabolic loop, and establish four results. First, the diabolic loop can be avoided by restricting banks' domestic sovereign exposures relative to their equity. Second, equity requirements can be lowered if banks only hold senior domestic sovereign...

In both the subprime crisis and the euro-area crisis, regulators imposed bans on short sales, aimed mainly at preventing stock price turbulence from destabilizing financial institutions. Contrary to the regulators’ intentions, financial institutions whose stocks were banned experienced greater...