Stock index futures pointed to a gain of about 1 percent at the open on Tuesday in a rebound from the previous session's nosedive, but an upcoming Fed statement could spark a reversal if investors are not convinced it has a plan to combat a market meltdown.

Equities suffered a massive decline on Monday, the first session since the United States lost it top-tier credit rating, with the S&P posting its worst one-day loss since December 2008 and nearing bear market territory.

Both the S&P and Nasdaq sank more than 6 percent and the Dow lost more than 5 percent on the heaviest trading volume since the flash crash in May 2010. The CBOE Volatility Index jumped 50 percent.

Federal Reserve policymakers began meeting Tuesday morning, and a Fed statement, due at 2:15 p.m EDT, will be scrutinized. While the central bank isn't expected to debut any massive new program to help asset prices, investors may return to selling if there's no indication that help is on the way.

Everyone is looking for a re-entry point into the market, but if (Fed Chairman Ben) Bernanke doesn't suggest a stronger policy, that will affect the market negatively, said Paul Radeke, vice president at the Minneapolis-based KDV Wealth Management.

The gains could last through the day, but there's a lot of negative bias, and everyone has their finger on the selling trigger.

Standard & Poor's downgrade of the U.S. credit rating late Friday, removing the nation's triple-A designation for the first time in history, sparked the decline and underlined fears a recession was inevitable given increasing signs of slowing growth and more turmoil in the euro zone.

S&P 500 futures rose 15.8 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 135 points, and Nasdaq 100 futures rose 35 points.

Even though fear remained a dominant emotion in the markets, analysts said stocks could be nearing a bottom. They noted the S&P was now more technically oversold than at any other time in the last ten years, with its 14-day relative strength index was at 16.5 percent. Generally a level below 20 attracts buyers.

Bank of America Corp, the S&P's biggest decliner on Monday, climbed 5.8 percent to $6.89 in premarket trading.

Adding to global concerns, China's annual inflation quickened to a higher-than-expected 6.5 percent in July, putting its central bank in a bind as it tries to keep prices in check without dragging down an economy facing increasing threats from abroad.

Overseas, the FTSEurofirst 300 index of top European shares dipped 0.2 percent, while Hong Kong index slumped 5.7 percent to its lowest since June 2010.

Dow component Walt Disney Co is scheduled to report quarterly results later Tuesday, with investors watching for an outlook on its theme park business in the midst of economic uncertainty.

AOL Inc reported a second-quarter loss but revenue fell less than expected.

Every S&P 500 component ended in negative territory in Monday's selloff, with all ten S&P sectors losing more than 3.5 percent. At its low, the Dow fell under 11,000 for the first time since November.

(Editing by Jeffrey Benkoe)