(Bloomberg) — U.S. stocks tumbled Tuesday, with the Dow Jones Industrial Average poised for its worst day since October, as a drop in durable-goods orders and disappointing results from Caterpillar Inc. to Microsoft Corp. heightened concern about the economy's strength.

Technology shares in the Standard & Poor's 500 Index had the biggest drop in more than three year. Microsoft lost 9 percent as software-license sales to businesses were below forecasts. Caterpillar plunged 7.5 percent after forecasting 2015 results that trailed estimates as plunging oil prices signal lower demand from energy companies. DuPont Co. dropped 2.8 percent as a stronger dollar cuts into the chemical maker's profit. Procter & Gamble Co. and United Technologies Corp. declined at least 1.3 percent after saying the surging greenback will lower full-year earnings.

"Currency headwinds, as well as evidence of a continual deceleration of global growth, is having a major impacts on quarterly results," Chad Morganlander, a money manager at St. Louis-based Stifel, Nicolaus & Co., which oversees about $160 billion, said in a phone interview. "Coupled with that, durable goods orders were somewhat disappointing, which scotches any optimism for today's trading session."