"We had seen the pendulum swing since Monday in favor of the bears," Pado said. The weak data, including a slowdown in private sector jobs growth, provided "a nudge in the direction we were already going."
Long-term investors weren't all shaken by the day's downdraft. "The long-term trends in the markets are still favorable, still going up," said Mebane Faber, cofounder and portfolio manager at Cambria Investment Management.
Cambria runs an actively traded exchange-traded fund that invests in U.S. and global stocks as well as currencies, commodities, bonds and real estate. The fund is fully invested across all asset classes, although it is short the dollar in favor of foreign currencies, and has a "half weighting," in financials, because the long-term trends point lower.
The portfolio also continues to have a long-term investment in precious metals and energy, although they have scaled back in base metals and agriculture, Faber said.
On the tech front, Apple traded flat. Before 11 a.m. ET, a single trade of 100 shares, executed at a sharply lower price, was cancelled, BATS Exchange confirmed.
And Intel gained after the company said it redesigned the electronic switches on its chips, known as transistors, to allow it to make the switches cheaper and faster.
In M&A, Ralcorp Holdings surged to new highs after news ConAgra Foods proposed to buy the Post brand cereals maker and other food products for $4.9 billion in cash. ConAgra, which owns Dennison’s and Swiss Miss brands as well as commercial food products, also gained.