Only one big surprise in Citigroup’s (C) third quarter earnings announced before the New York Stock market opened October 18.

No, not the penny a share in earnings above the Wall Street estimate of 6 cents a share. A slight positive surprise certain was a high probability event after JPMorgan Chase (JPM) surprised last week.

No, not the decline in revenue to $20.74 billion, below the analyst consensus of $21.15 billion and down 5.7% from the third quarter of 2009. That is exactly the problem that JPMorgan Chase reported too and it points to the problems that U.S. banks are having in generating growth in their core business.

No, not even the drop in credit losses that led to the release of reserves against loan losses of about $1.96 billion for the quarter. That’s the expected story at this point in the bank recovery. And indeed the boost to earnings that a bank can get from reducing its loan loss reserves has been the expected story for two or three quarters now.

The surprise is that Citigroup didn’t put any money aside against lawsuits or delays in mortgage foreclosures because of the current investigation into inadequately documented foreclosures. Investigations being conducted by all 50 states attorney generals are looking into what have been dubbed “robo signers” who certified mortgages for foreclosure without checking to see that foreclosure documents were adequate.

On October 13 as part of its third quarter earnings report JPMorgan Chase added $1.3 billion to its reserves against mortgage-related litigation.

Citigroup has said that it has found no evidence of robo signing during an intensive internal review.

Unlike such peers as JPMorgan Chase, Bank of America (BAC), and Wells Fargo (WFC), which have all declared foreclosure moratorium as inside and outside investigations unwind, Citigroup continues to foreclose on mortgages that it originated.