US stocks swoon, led by a slump in energy shares as oil price falls; Dow's worst drop of 2014

It was another wild ride for the stock market as the Dow Jones industrial average had its biggest plunge of the year.

The 334-point drop came a day after the Dow had its biggest gain of the year.

The Dow hasn't had this many big swings since August of 2011, when the U.S. government lost its AAA credit rating.

Energy stocks led the slide as the price of oil continued to slump. Oil fell 2 percent on worries that the global economy will slow even as production remains high. Chevron fell 3 percent.

At the closing bell the Dow was down nearly 2 percent at 16,659.

The Standard and Poor's 500 fell 40 points, or 2.1 percent, to 1,928. The Nasdaq composite fell 90 points, or 2 percent, to 4,378.