Major U.S. indexes stood stock-still for the third consecutive day Thursday as gains for retailers were cancelled out by losses for banks and other companies.
The S&P 500 index slipped after coming within spitting distance of a record high following a four-day rise.
The Dow slid 149.44 points, or 0.6 per cent.
Microchip Technology shares fell 11.6 percent after disappointing second-quarter revenue forecast.
The Canadian dollar averaged 76.26 cents U.S., down 0.43 of a United States cent.More news: Emery in spotlight as Arsenal begin life without Wenger
Investors fled to safe-haven assets, with the dollar rising to a 13-month high and USA bond yields slipping to a three-week low.
"Today's impact has set the markets in a temporary risk-off sentiment", said Matt Forester, chief investment officer of BNY Mellon's Lockwood Advisors.
At 2:47 p.m. (1847 GMT), the Dow Jones Industrial Average was down 270.25 points, or 1.06 percent, to 25,238.98, the S&P 500 had lost 25.21 points, or 0.88 percent, to 2,828.37 and the Nasdaq Composite had dropped 65.17 points, or 0.83 percent, to 7,826.61.
Chip stocks fell after Morgan Stanley downgraded the USA semiconductor industry saying upside to estimates is hard to come by.
The S&P 500 is up 179.97 points, or 6.7 per cent.More news: 'Stolen' plane closes Seattle airport before crashing into sea
For the week, the Dow fell 0.6 per cent and the S&P 500 dipped 0.3 per cent.
Shares of trade-sensitive companies declined, with Boeing, 3M and Caterpillar down between 2.3 percent and 4 percent.
Data on Friday showed US consumer prices rose in July and the underlying trend continued to strengthen, pointing to a steady increase in inflation pressures.
Declining issues outnumbered advancing ones on the NYSE by a 1.04-to-1 ratio; on Nasdaq, a 1.10-to-1 ratio favored advancers. Excluding the energy sector, the earnings growth estimate declines to 20.4 percent, according to Thomson Reuters.More news: Richarlison strikes twice but 10-man Everton held at Wolves