A bank publishes lousy earnings or an “update” on its business. Its share price plunges. Its name is splashed on newspaper front pages. The bank’s bosses hold a conference call urging calm. Its share price slides some more. Anyone who has paid attention to America’s banking industry over the past year will recognise these events. They ended in failure for Silicon Valley Bank (SVB) in March and First Republic Bank (FRB) in April.