The Labor Department said initial jobless claims rose by 46,000 to 388,000 a week after a drop of 30,000 claims the previous week had put the weekly number at a 56-month low.
A reversal had been expected, but not one quite so dramatic.
By close of trading, the Dow Jones industrial average shed 8.06 points, or 0.06 percent, to 13,548.94. The Nasdaq composite index was down 31.26, or 1.01 percent, to 3,072.87. The Standard and Poor's 500 index lost 3.57 points, or 0.24 percent, to 1,457.34.
On the New York Stock Exchange, 1,482 stocks advanced and 1,545 declined on a volume of 3.8 billion shares traded.
The benchmark 10-year treasury note fell 3/32 to yield 1.835 percent.
The euro fell to $1.3066 from Wednesday's $1.312. Against the yen, the dollar rose to 79.26 yen from 78.97 yen.
In Japan, the Nikkei 225 index added 2 percent, 176.31 points, to 8,982.86.
In London, the FTSE 100 index gained 0.1 percent, 6.14, to 5,917.05.