The scene was reminiscent of the last financial crisis, nearly 15 years ago: Faced with a blossoming emergency in the banking sector, worried regulators and policymakers in Washington turned to Wall Street for help. The anxiety this week centred on First Republic Bank in San Francisco, which was once the envy of the banking sector, with its wealthy and well-travelled clientele. Now the bank was reeling after some of those customers withdrew billions of dollars.