Washington ? American International Group will gain access to $30 billion more in taxpayer money as part of another restructuring of its federal bailout, sources involved in the negotiations said Sunday. It marks the fourth time the government has stepped in to save the ailing insurance giant since September.

The reworked plan is aimed in part at helping AIG avert a potential disaster as it announces the biggest quarterly corporate loss in history this morning — more than $60 billion for the fourth quarter of 2008, according to sources who spoke on condition of anonymity because the results had not yet been released. The government reaction is rooted in the idea that AIG, which has ties to nearly every major financial institution in the world, cannot be allowed to fail.

Credit-rating agencies would have likely downgraded AIG in the face of such staggering losses, sources said, burying the company in a wave of new debt and possibly sending it into bankruptcy protection.

But the commitment of new funds from the Treasury Department’s Troubled Assets Relief Program is meant to demonstrate that AIG can make good on its public and private debts and that the company could return viability

“It buys time,” said one source involved in the discussions, adding that AIG isn’t expected to access the money immediately.

The additional federal money is one part of the restructuring that AIG’s board of directors approved Sunday. As part of an effort to pay back its outstanding Federal Reserve loan, AIG will give the government equity stakes in two of the company’s crown jewels, Asian-based American International Assurance Co., and American Life Insurance Co., which operates in more than 50 countries. Each subsidiary will be placed in a separate trust, removing both from AIG’s books, and the government will have direct ownership. AIG will continue to operate the companies, however, and could sell or take them public.

The revamped deal allows AIG to free itself from the 10 percent dividend it previously had to pay the government on its preferred shares, a move that will save billions annually. The government also has agreed to purchase a sizable chunk, or securitize, AIG’s domestic life insurance business for $7 billion $10 billion, sources said. It could then choose to sell that business or simply take in the steady income it provides.

The reworked bailout package acknowledges that AIG’s strategy of selling off two-thirds of its assets to pay back the government within two years was not working. In recent months, the market for those assets continued to plummet as the economy worsened, and already-hesitant buyers were facing their own credit problems.

“This expands the number of options,” said one source involved in the restructuring. “Alternatives are a good thing.”

The new deal, however, will leave the federal government more deeply intertwined with AIG, all but assuring that taxpayers will remain involved with the company for years.

But sources close to the negotiations said AIG still poses a very real risk to the global financial system.