The program has remained unpopular with the public despite its lowered costs.
"It was not apparent when the TARP was created two years ago that the costs would be this low," CBO Director Doug Elmendorf said in a blog post.
When the legislation was passed, the financial system was in a "precarious condition" and the TARP "engendered substantial financial risk for the federal government."
"However, the cost has come out toward the low end of the range of possible outcomes anticipated when the program was launched," he said. "Because the financial system stabilized and then improved, the amount of funds used by the TARP was well below the $700 billion initially authorized, and the outcomes of most transactions made through the TARP were favorable for the federal government."
That cost -- $45 billion -- stems largely from assistance to American International Group (AIG), aid to the automotive industry and grant programs aimed at avoiding mortgage foreclosures. Other transactions will, taken together, result in a net gain of $20 billion to the federal government, CBO estimates.
TARP, which expired in October, has distributed $389 billion and CBO estimates that an additional $44 billion more will be provided, most of it to AIG and federal mortgage programs. The restructured AIG bailout is expected to cost $14 billion instead of the initial estimate of $70 billion.
About $216 billion has been repaid of the $433 billion total spent by TARP.
AIG's losses are expected to be covered by that $20 billion in profits from other TARP investments, the report said.
Treasury also is expected to recoup a greater share of the assistance provided to General Motors and Chrysler. The federal government made $12 billion after GM's successful initial public offering. The total cost is expected to come in around $19 billion, much less than expected, the report said.