The most persuasive way to convince bank creditors that their bank isn't too big to fail (TBTF) is for policymakers to reduce systemic risk and to communicate those steps to the public.

A proposed bank merger and acquisition (M&A) provides a unique opportunity to address too big to fail concerns—the problem of big banks taking undue risks due to creditors’ perceptions that government policymakers will bail them out to prevent spillovers from bank collapse. Under a...