At perhaps the final results presentation of his banking career, would Ken Lewis have liked Friday’s hotchpotch of one-offs to add up to a positive number? Of course he would. Rivals JPMorgan and Goldman Sachs posted frankly eye-watering profits this week. But although the reputation of the outgoing chief executive of Bank of America is in the mud, his true legacy will not be clear for years.

Leave aside that BofA paid too much for Merrill Lynch. No one will ever know the political pressures at work during those frightening moments of last year. But which bank today wouldn’t rather have Merrill in its fold, than, say, Wachovia or Washington Mutual? The irony is that not long ago everyone thought investment banking was going to implode or be regulated to death. As the west deleverages, though, it is consumer banking that faces years of misery ahead. Meanwhile, BofA’s core global banking and global markets divisions account for about 40 per cent of pre-tax, pre-provision earnings, according to Citigroup.

Imagine America’s biggest lender without investment banking. Uncollectable loans were up by a 10th versus the previous quarter. Mortgage volumes were down, and those not accruing interest jumped 14 per cent. Over $1bn a quarter is being lost in credit cards as provision levels remain elevated. A rebound in markets has helped Merrill’s “thundering herd” of brokers turn a profit but, at $271m, it is a rounding error in context of the whole bank.

So thank goodness for Merrill. For investors who also believe the US consumer is on the mend, BofA would be a big winner as well as very cheap on any rosy “normalised” earnings basis. Indeed, the bank itself was seeing improving delinquencies on its unsecured consumer portfolios, and overall provisions for credit losses were lower. Mr Lewis may yet be remembered fondly down the road.