The Dow Jones industrial average plunged more than 300 points and erased its gains for the year as investors grew more concerned about economic weakness in the U.S. and Europe.

The Standard & Poor’s 500 index fell more than 3 percent, bringing it 10 percent below its recent high of 1,363 reached on April 29. A decline of 10 percent is considered to be a market correction. The Dow Jones industrial average is now down more than 1,100 points from July 21.

Oil fell 4 percent to $88 a barrel on worries demand will fall because of the slowing economy. Oil had traded over $100 as recently as June 9.

“We are continuing to be bombarded by worries about the global economy,” said Bill Stone, chief investment strategist at PNC Financial.

If the market closes “down” again today, it will mark the ninth straight day of losses, which has not occurred on the markets since February 1978.