U.S. stock index futures pointed to a lower open on Wall Street on Tuesday as investors braced for aluminum producer Alcoa's quarterly results that will kick-start a keenly awaited U.S. earnings season.

* At 4:45 a.m. EDT, futures for the S&P 500 were down 0.9 percent, Dow Jones futures were down 0.8 percent and Nasdaq 100 futures were down 0.7 percent.

* European shares surrendered initial gains and turned negative in morning trade on Tuesday, down 1.1 percent.

* On the macro side, the Bank of Japan unveiled further steps to ease credit strains on Tuesday, while Australia's central bank cut its key cash rate by 25 basis points to 3.00 percent, the sixth easing in eight months.

* Toxic debts racked up by banks and insurers could spiral to $4 trillion, new forecasts from the International Monetary Fund are set to suggest, British daily The Times reported on its website without citing sources. The IMF said in January that it expected the deterioration in U.S.-originated assets to reach $2.2 trillion by the end of next year.

* A half-dozen bidders have emerged for American International Group Inc's asset-management unit, but the sale of the $100 billion portfolio has become complicated by client withdrawals and declines in asset prices.

* General Motors Corp's request for $10.3 billion in loans under a U.S. Department of Energy program is now contingent on the automaker's 60-day restructuring review, a top GM executive said on Monday. Treasury wants to fully understand what our ultimate destiny is before giving us that (DOE) loan, GM Vice President of Research and Development and Strategic Planning Larry Burns told Reuters on the sidelines of a product briefing on Monday.

* Ford Motor Co said its investors agreed to exchange $9.9 billion in debt for cash and stock, ratcheting up the pressure on its struggling U.S. competitors that also are trying to cut debt.

* A major client for Applied Materials Inc's solar production gear has slashed its order by more than 85 percent to $250 million, underscoring how a deepening recession is eroding a once red-hot solar sector. Shares in Applied Materials, that has been steadily expanding its solar capacity to offset slowing sales of its semiconductor manufacturing equipment, slid 3.1 percent to $11.20 in after-hours trade.

* Bank of America's Merrill Lynch said on Tuesday that it had recently closed the Tokyo office of Merrill Lynch Global Private Equity, a major international investment arm of the U.S. bank. Sources with direct knowledge of the matter told Reuters that the closure of its Tokyo office was due mainly to lack of deal flow in Japan's private equity markets.

* U.S. shares snapped a four-session winning run on Monday after a prominent analyst reignited fears over the health of banks and the potential collapse of a takeover of Sun Microsystems bruised sentiment in the technology sector.

* The Dow Jones industrial average <.DJI> fell 41.74 points, or 0.52 percent, to 7,975.85. The Standard & Poor's 500 Index <.SPX> lost 7.02 points, or 0.83 percent, to 835.48. The Nasdaq Composite Index <.IXIC> was down 15.16 points, or 0.93 percent, at 1,606.71.

(Reporting by Blaise Robinson; editing by John Stonestreet)