Stock index futures pointed to a lower open on Tuesday, with the S&P 500 set to enter a bear market as European officials postponed a vital aid payment to debt-stricken Greece.

Wall Street stocks dropped to 13-month lows on Monday as investors feared the crisis in Europe could increase the chances of a new recession in the United States.

Adding to market pessimism, Goldman Sachs cut its gross domestic product outlook for advanced economies for 2012, lowering its growth forecast to 1.3 percent from 2.1 percent.

The main driver of our shift in views has been the escalation of bank funding stress in the Euro area, alongside deeper public budget cuts in a number of European countries, Goldman said in a note.

The STOXX Europe 600 Banking Index <.SX7P> sank 4.6 percent on Tuesday as European officials reviewed a plan for banks to take bigger losses on Greek debt and on expectations Greece would default soon.

Franco-Belgian bank Dexia dropped 14.5 percent to a record low as investors focused on its heavy exposure to Greek debt. European shares tumbled 2.8 percent. <.EU>

U.S. banks were likely to remain in focus and continue to be pressured by the same issue. Morgan Stanley was down about 4 percent to $11.96 in premarket trading. On Monday, it closed at its lowest since December 2008.

European finance ministers were considering making banks take bigger losses on Greek debt and delayed a vital aid payment to Athens until mid-November.

The economy is in a protracted slowdown, and until there's a resolution with Greece, that situation will continue to linger over the market, said Robert Pavlik, chief market strategist at Banyan Partners LLC in New York. This could turn into a self-fulfilling prophecy of recession.

S&P 500 futures fell 6.3 points and were below 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 sank 93 points, and Nasdaq 100 futures lost 12.25 points.

The benchmark S&P is down 19.4 percent from a high set on April 29. It would have to be down 20 percent to enter bear market territory.

Later Tuesday, U.S. Federal Reserve Chairman Ben Bernanke will testify before the Joint Economic Committee in Washington on the economic outlook.

Data on durable goods and factory orders, both for August, will also be released at 10 a.m. EDT. Factory orders are seen unchanged from the prior month.

Apple Inc is expected to unveil a new version of its popular iPhone, hoping to fend off hard-charging rivals running Google Inc's Android system. The stock was very slightly higher in premarket trading.

Ford Motor Co edged 1.2 percent lower to $9.26 in premarket trading after reaching a tentative agreement with the United Auto Workers union on a new contract.

Fast food chain operator Yum! Brands Inc is on tap to report quarterly results.

The Dow and S&P dropped more than 2 percent on Monday, slumping to 13-month lows in heavy volume on fears Greece's debt woes could spark a full-blown banking crisis in Europe. The Nasdaq fell more than 3 percent.

(Editing by Jeffrey Benkoe)