Zandi estimated that all but $100 billion to $150 billion would be returned to taxpayers, a much better return than predicted last fall. But that won't change the American public's opinion of the program, he said.
"They're still going to say it cost us $100 billion to $150 billion and all it did was save Wall Street," Zandi said. "There's no way to sugarcoat this: TARP is a black mark on our economic history. But we had to do it. The world without it would have been immeasurably darker."
There's a widespread consensus that TARP shored up confidence in the global financial sector and paved the way for a dramatic rebound in Wall Street profits.
"The end result is hard to debate," said Adam Sussman, research director at Tabb Group, a research firm. "The banks are more stable now than when TARP was initiated. Overall the efforts to restore financial stability have been successful by any measure."
But even some on Wall Street acknowledge that a secondary rationale offered for the infusions of government capital into banks -- that a restored financial sector would help the economy rebound -- hasn't panned out.
"This worked extraordinarily well for Wall Street, but it has failed utterly for the real world," said Don Putnam, managing partner at Grail Partners, a boutique investment bank in San Francisco.
TARP and other government programs breathed life into the financial markets, which boosted demand for basic Wall Street services such as stock trading, corporate capital raising and the construction of exotic, often lucrative financial instruments known as derivatives.
But some analysts worry because TARP didn't help banks purge the mountains of toxic assets that sparked the financial crisis, which could restrain their lending going forward.
"TARP has given us the illusion that the banks are on the mend," said Christopher Whalen, managing director of Institutional Risk Analytics in Torrance. "But the losses that banks face on some assets are going to be so big that the real economy is going to end up dying before the banks can heal themselves."
Not everyone is so glum.
Many see the resurgence of Wall Street as a crucial first step toward broader recovery. But the resuscitation of the banking industry could be short-lived if unemployment stays high and consumers remain wary of spending.
"The financial sector's recovery won't last unless there is a subsequent recovery in the broader economy," Sussman said. "So far what's happened has been good, but it doesn't mean we can breathe a sigh of relief yet."
For that reason, Zandi said the Obama administration should extend the TARP program, even if that limits the potential return to taxpayers.
"I don't think we can declare that the coast is clear," he said. "We need to have this as an insurance policy.