The trend toward greater provision of payments services by nonbank providers raises a question for regulators: What if these nonbank institutions suffer unfavorable balances or experience a run? The authors of this article look to the Panic of 1907 as an example of how private market participants, in the absence of government institutions, react to a crisis in their industry. They suggest that New York's and Chicago's contrasting experiences during the panic may provide useful lessons for both regulators and market participants. ; The article compares responses to the panic by bank intermediaries in the two cities through clearinghouses. The apparent isolation of trusts from the New York Clearinghouse left the clearinghouse with inadequate knowledge of their condition and hindered prompt action. In Chicago, the clearinghouse had timely information on most intermediaries in the city, including the trusts, and therefore was positioned to react quickly. ; The distinct nature of the Panic of 1907 and the differences between private market regulation through clearinghouses and the current framework of public regulation limit recommendations for today's financial world. Nonetheless, the historical experience provides a precedent for the development and growth of payments services offered by nonbank providers, which should not be ignored as key players in the payments system. The key lesson from history is that such ignorance can be expensive.