This is what is happening.
For the first 2 months of the 1st quarter, Citi group has been booking monthly revenue and expenses from its operating lines of business. These typically operate at a profit. Given the fact Citi can borrow essentially at zero, they're turning a profit.
At the end of the 1st quarter (the end of March), Citi will have to assess the assets like CDO's, CLO's, RMBS, CMBS still sitting on its balance sheet. Given there is no market for these, they will incur further massive writedowns which will obliterate any operating line profits they have.
How could they avoid burying those profits underneath all the shitty assets they have? Why, how about we get rid of the mark-to-market rule for illiquid assets?
Done. Barney Frank is on it.
Anyone who buys Citi on accounting gimmicks is a fool.