Add $100 oil to billions in bank write-offs and it should come as no surprise that the word “recession” is being heard with increased frequency. As is the view that circumstances have combined to neuter the Fed, making it powerless to use its monetary policy weapon to prevent a downturn.

It’s not the write-offs that have nerves on edge so much as it is the inability of the chiefs of the major banks to come close to estimating the magnitude of the problem.