But the strong start of the funds has pushed aside many of those concerns.

“We feel very good about the performance to date,” said David N. Miller, the Treasury Department’s chief investment officer who oversees its bailout-related holdings.

The administration has not yet provided its own profit projections, and all proceeds will be used to pay down the nation’s ballooning debt. But any windfall, Mr. Miller suggested, would be icing on the cake for taxpayers.

The program’s main benefit, he said, has been to help revive the market for complex mortgage bonds, whose trading ground to a halt a year and a half ago. That helped break the downward spiral of asset prices and paved the way for a wave of new bond deals, which lenders rely on to finance new mortgages.

“We view that as accomplishing the mission,” Mr. Miller said.

The scope of the government’s action was scaled back before it got started. In fact, the original purpose of the $700 billion federal bailout program, authorized by Congress during the tenure of Treasury Secretary Henry M. Paulson Jr., was to buy mortgage assets much more aggressively. Instead, that money was used to make direct investments in troubled banks.

So, to restart the trading of mortgage assets, the incoming Treasury secretary, Timothy F. Geithner, announced the creation of a smaller Public-Private Investment Program. The administration hoped to establish market prices for the assets so that banks would not have to sell them at fire-sale prices, which would have threatened their solvency.

As a side effect, though, the extraordinary government interventions in the banking system made necessary by the financial crisis have turned the United States government into one of the world’s biggest vulture investors.