“It was probably the only effective method available to us to keep from having a financial meltdown much worse than we actually had. Had that happened, unemployment would be substantially higher than it is now, the deficit would have gone up even more than it has,” Mr. Elliott added. “But it really cuts against the grain for a public that is so angry at banks to think that something that so plainly helped the banks could also be good for the public.”

After Sunday the Treasury can no longer commit money to new initiatives or recycle repayments to other purposes.

The Treasury never tapped the full $700 billion. It committed $470 billion and has disbursed $387 billion, mostly to hundreds of banks and later to A.I.G., the car industry  Chrysler, General Motors, the G.M. financing company and suppliers  and to what is, so far, a failed effort to help homeowners avoid foreclosures.

When Mr. Obama took office, the financial system remained so weak that his first budget indicated the Treasury might need another $750 billion for TARP. The administration soon dropped that idea as Mr. Geithner overhauled the rescue program and the banking system stabilized. Still, by mid-2009, the administration projected that TARP could lose $341 billion, a figure that reflected new commitments to A.I.G. and the auto industry.

The Congressional Budget Office, which had a slightly higher loss estimate initially, in August reduced that to $66 billion.

Now Treasury reckons that taxpayers will lose less than $50 billion at worst, but at best could break even or even make money. Its best-case assumptions, however, assume that A.I.G. and the auto companies will remain profitable and that Treasury will get a good price as it sells its corporate shares in coming years.

“We’d have to be very lucky to have both A.I.G. and the auto companies pay us back in full,” Mr. Elliott said.