The Dow Jones industrial average plunged 217 points, its biggest drop in six weeks, to close at 14,960 Wednesday, a loss of 1.4 per cent.
It's the first time the Dow has closed below 15,000 in a month. Intel led the Dow lower.
Several reports suggested the economy is slowing, including weakness in hiring at private companies, a drop in mortgage applications and sluggish service-sector job growth.
The Standard & Poor's 500 index fell 22 points, or 1.4 per cent, to 1,608.
The Nasdaq fell 43 points to 3,401, a loss of 1.3 per cent.
Five stocks fell for every one that rose on the New York Stock Exchange. Volume was average, 3.6 billion shares.