Stock index futures pointed to a weaker open for equities on Wall Street Wednesday, with futures for the S&P 500, for the Dow Jones and for the Nasdaq 100 down 0.4-0.7 percent.

Standard & Poor's reduced its credit ratings on 15 big banking companies, mostly in the Europe and the United States, on Tuesday as the result of a sweeping overhaul of its ratings criteria.

JPMorgan Chase & Co, Bank of America Corp, Citigroup Inc, Wells Fargo & Co, Goldman Sachs Group Inc, Morgan Stanley, Barclays Plc, HSBC Holdings Plc, Royal Bank of Scotland Group Plc and UBS AG were among the banks that had their ratings reduced by one notch each.

The ADP Employment report for November, due at 1315 GMT, is expected to show its best reading since April and the third consecutive gain greater than 110,000. The Pending Home Sales Index, to be released at 1500 GMT, is seen rising for October.

Samsung Electronics <005930.KS> is set to resume selling its Galaxy tablet computer in Australia as early as Friday, after the South Korean technology firm won a rare legal victory in a long-running global patent war with Apple Inc.

Boeing could be at a disadvantage to Airbus because the bankruptcy of AMR Corp, the parent of American Airlines, places up to $40 billion of jet orders at the mercy of a U.S. bankruptcy court, lawyers and bankruptcy experts said.

Newmont Mining Corp said it has suspended construction work at its Conga project in Peru in agreement with the government, for the safety of employees and the community.

U.S. communications regulators released a staff report criticizing AT&T Inc's $39 billion plan to purchase T-Mobile USA, even though they agreed on Tuesday to let the companies withdraw their request for approval.

Goldman Sachs has raised $600 million from clients such as pension funds, wealthy families and large institutions for a new fund that would provide start-up money to hedge-fund managers, the Wall Street Journal said.

European stocks <.FTEU3> fell 0.8 percent on Wednesday, snapping a sharp three-session rally, after the Standard & Poor's downgrade of a number of European and U.S. banks.

On Tuesday, the Dow and S&P 500 advanced for a second day on Tuesday as stronger-than-expected consumer confidence data and hopes for further progress on a solution to Europe's fiscal mess bolstered sentiment.

Euro zone ministers agreed to ramp up the firepower of their rescue fund, but couldn't say by how much, and may turn to the IMF for more help as a jump in Italy's borrowing costs pushed the region closer to financial disaster.

The Dow Jones industrial average <.DJI> closed up 32.62 points, or 0.28 percent, at 11,555.63. The Standard & Poor's 500 Index <.SPX> ended up 2.64 points, or 0.22 percent, at 1,195.19. The Nasdaq composite index <.IXIC> closed down 11.83 points, or 0.47 percent, at 2,515.51.

(Reporting by Atul Prakash. Editing by Jane Merriman)