They say “assume” stands for making an Ass out of U and Me. Certainly, the US’s bank stress tests contain enough assumptions to make an investor’s head spin. The main ones fall into two buckets. Those used to estimate losses on assets are largely supported by the banks. By contrast, the Treasury’s earning forecasts have been challenged by at least four of the 19 banks, not unsurprisingly.

Where assumption leads, spin follows. The stress tests concluded that Citigroup, for example, will make pre-provision net earnings of $49bn over the next two years – a run rate of $25bn per year. Outrageous, argues the bank in a presentation released immediately after the results, showing average quarterly pre-provision earnings since the beginning of 2007 at about $10bn. That equates to $80bn by 2010. The trouble is, Citi does not include writedowns, the main source of capital destruction since the credit crunch began.