Stock index futures pointed to a lower open on Wall Street Tuesday following a brisk rally, with futures for the S&P 500 down 0.7 percent, Dow Jones futures down 0.6 percent, and Nasdaq 100 futures down 0.4 percent at 0938 GMT.

The focus will be on the start of the earnings season, with results due from aluminum major Alcoa , as investors seek insight on the extend of the damage from a global slowdown in economic growth.

European stocks were down 0.6 percent in morning trade, halting a brisk four-session rally as investors book some profits ahead of Slovakia's parliamentary vote to ratify an expansion of the euro zone's rescue fund. All 17 euro zone states must ratify the EFSF expansion for it to take effect.

The euro zone sovereign debt crisis has become systemic, and risks to the economy are increasing rapidly with Europe's banks in the danger zone, European Systemic Risk Board Chairman Jean-Claude Trichet said Tuesday.

Trichet, who heads the European Central Bank as well as the continent's super-watchdog on financial stability, said the euro zone's EFSF bailout fund should be made as flexible as possible, but without involving the ECB in leveraging it.

Asian shares rose Tuesday after China moved to support its stock market by buying shares in major banks, fuelling speculation that the country might be on the path to interest rate cuts.

U.S. regulators Tuesday are set to give nervous insurance companies, mutual funds and other big players in financial markets a better idea of whether they will be tapped for the same type of additional government scrutiny facing large U.S. banks.

Privately held U.S. oil and gas explorer Samson Investment Co is considering strategic options including whether to sell itself in a deal that could fetch as much as $10 billion, the Wall Street Journal said, citing people familiar with the matter.

U.S. stocks jumped 3 percent on Monday, extending gains into a second week as a pledge by German and French leaders boosted hopes that the euro-zone debt crisis may be resolved.

The Dow Jones industrial average <.DJI> surged 330.06 points, or 2.97 percent, to end at 11,433.18. The Standard & Poor's 500 Index <.SPX> climbed 39.43 points, or 3.41 percent, to 1,194.89. The Nasdaq Composite Index <.IXIC> shot up 86.70 points, or 3.5 percent, to close at 2,566.05.

The gains lifted the S&P 500 above its 50-day moving average for the first time since late July, a bullish technical signal.

(Reporting by Blaise Robinson; Editing by Will Waterman)