US stocks have fallen to their biggest loss in six weeks as banks and technology companies tumbled.
Interest rates moved lower, hurting financial stocks, while the dollar continued to fall compared to the Japanese yen. Stocks have fallen for three out of four days this week.
Stocks sharply reversed course after their gains a day ago.
Financial companies including Goldman Sachs and Citigroup took the largest losses, while technology and telecommunications companies also fell.
The market has lost momentum over the last few weeks after a furious rally that wiped out most of its losses from early 2016.
Scott Wren, senior global equity strategist for Wells Fargo's Investment Institute, said stocks are rising and falling based on how investors expect the global economy to do.
"People are worried about growth today," he said. "You're not getting much more than modest economic activity."
The Dow Jones industrial average fell 174.09 points, or 1%, to 17,541.96. The Standard & Poor's 500 index shed 24.75 points, or 1.2%, to 2,041.91. The Nasdaq composite index lost 72.35 points, or 1.5%, to 4,848.37.