The original WSJ article that Wikipedia got that from is here.

Other people point out the that Treasury Department, which has a huge stake in their program being successful, overlooks a few things:

^Of course, there’s a small problem with all this happy Washington math: it doesn’t take into account the piles of cash we’re likely to lose on Fannie Mae and Freddie Mac, the huge mortgage finance companies. The Congressional Budget Office estimates that figure to be about $320 billion. That would wipe away any gains made elsewhere. ^

^The overall math also doesn’t account for the more than $1 trillion the Federal Reserve pumped into the system through loans to Wall Street that were virtually interest-free.^