New York - The giant insurance conglomerate American International Group (AIG) remained tottering on the brink of collapse Tuesday, with no end in sight to emergency rescue talks between company executives, government officials and private stakeholders.

As time was quickly running out, there was still no outcome Tuesday afternoon from five-day-long talks at the New York Federal Reserve. AIG in a statement said it was continuing to pursue a variety of options.

AIG, the largest US insurer, needs as much as 75 billion dollars in loans to stay afloat. Three major US credit rating agencies downgraded AIG's standing Tuesday morning.

New York Governor David Patterson told CNBC that AIG had only one day to raise the needed cash. But it was unclear where the much- needed capital might come from.

AIG had originally turned to the Federal Reserve for a 40-billion- dollar bridge loan, seen as a life-support until AIG can sell off some of its assets and regain firm footing.

US Treasury Secretary Henry Paulson appeared to rule that out in a press conference Monday, but media reports indicated the Fed may be reconsidering that position.

The Fed has already pledged to spend up to 200 billion dollars of taxpayer money to help rescue the government-chartered mortgage giants Fannie Mae and Freddie, and backed another 29 billion dollar loan for the purchase of troubled investment banking firm, Bear Stearns, by JP Morgan Chase.

The Treasury was even considering going a similar route with AIG, placing it in a conservatorship along the lines of the government takeover of Fannie and Freddie last week, Bloomberg financial news reported.

A bankruptcy filing by AIG, a huge world player in insuring risk for institutions, would have an even greater impact on the US and global finance system than Monday's bankruptcy by Lehman Brothers Holdings Inc, industry experts said.

"There's a systemic risk if AIG isn't saved," Benoit de Broissia, an equity analyst at Richelieu Finance in Paris, told Bloomberg Television.

AIG has sold protection to banks and other investors on 441 billion dollars of fixed-income assets, including 57.8 billion dollars in securities tied to the plunging subprime mortgage market, Bloomberg financial news agency reported.

The Fed on Monday was encouraging two Wall Street survivors, Goldman Sachs Group Inc and JP Morgan Chase & Co, to issue short-term loans totalling 75 billion dollars, but that option had reportedly fallen through by Tuesday afternoon.

Standard and Poor's, Moody's and Fitch lowered AIG's previous good-to-very-good credit rating to good-to-satisfactory after Monday's upheavals. The downgrading makes it more difficult for the struggling insurance giant to raise capital on financial markets to meet its obligations and invites clients to call for collateral.

The rating agencies also placed AIG under observation and did not rule out a further lowering of its credit-worthiness ratings.

A record rate of home foreclosures has decimated Wall Street's market for mortgage-backed securities. Similarly, AIG got involved in selling so-called credit-default swaps - contracts it sold to protect debt investments.

As the debt risk in mortgage securities soared, the company conceded last month it had sold the swap instruments too cheaply compared to the real risks, which have now been exposed.

Tuesday's rating cuts may trigger collateral calls for more than 13 billion dollars from debt investors who bought swaps, according to a filing by AIG last month.

AIG's assets include its consumer lender, American General Finance, a stake in the reinsurer Transatlantic Holdings Inc and an aircraft leasing unit International Lease Finance Corp. dpa (dpa)