U.S. stocks fell, putting the Standard & Poor’s 500 Index on pace for its worst month since September, after a gauge of pending home sales dropped by the most in a year and concern that Greece will leave the euro grew.

Global stocks slumped while U.S. Treasury 10-year yields slid to a record and the euro weakened to a two-year low. An opinion poll showed most Greeks want to see the terms of an international financial rescue revised. In the U.S., the index of pending home resales dropped 5.5 percent, figures from the National Association of Realtors showed today. The median forecast of economists surveyed called for no change.

Earlier today, equity futures briefly pared losses as the European Commission called for direct euro-area aid for troubled banks, and touted a Europe-wide deposit-guarantee system and common bond issuance as antidotes to the debt crisis now threatening to overwhelm Spain.

RIM sank 7.5 percent to $10.39, the lowest level since 2003. An exodus of customers to Apple Inc.’s iPhone and Google Inc.’s Android devices has taken a toll on sales and profit, putting pressure on management to make changes. An operating loss would be the company’s first since 2004.

Sears Holdings Corp., the department-store chain controlled by hedge fund manager Edward Lampert, and Kohl’s Corp. led declines in retail stocks ahead of tomorrow’s industrywide monthly sales report.

Sears, based in Hoffman Estates, Illinois, declined 8.6 percent to $52.55 for the largest drop in the S&P 500. Kohl’s slumped 2.7 percent to $49.25, while Macy’s Inc. fell 1.7 percent to $38.34.