Trust is ubiquitous in the financial system. Banks trust that customers will repay their loans. Depositors trust that banks will manage their money carefully. And banks trust other banks to provide liquidity and to remain standing day after day. But as Walter Bagehot – arguably the most prominent scholar of banking in modern history – noted in his famed account of London’s 1866 financial panic, trust in the financial system can erode from “hidden causes.” When trust is weakened, even seemingly small accidents – like the collapse of London bank Overend, Gurney, and Company, which triggered the panic – can cause systemic financial crises.