It may be difficult to feel sorry for anyone working on Wall Street, but if you are going to extend some seasonal sympathy this year, pity those analysts whose job is to work out what makes banks tick.

While they have fewer companies to cover after the demise of Bear Stearns and Lehman Brothers, and a frantic round of consolidation in the rest of the banking sector, they have also had to reinvent the metrics they deployed to measure the performance of banks in a pre-crisis world in which the numbers flattered to deceive.