The technology sector has been at the centre of a sharp recovery in USA stocks since a market rout in February.
Trade tensions have simmered throughout the strong earnings season, however.
The number of Americans filing for unemployment benefits unexpectedly fell last week, a Labor Department report showed.
The S&P 500 opened lower by 13.94 points, or 0.49 per cent, at 2,839.64.
In the week ending August 4, the advance figure for seasonally adjusted initial claims was 213,000, a decrease of 6,000 from the previous week's revised level, the Labor Department said on Thursday.
At 12:41 p.m. ET, the Dow Jones Industrial Average was down 175.04 points, or 0.69 percent, at 25,334.19, the S&P 500 was down 14.98 points, or 0.52 percent, at 2,838.60 and the Nasdaq Composite was down 27.87 points, or 0.35 percent, at 7,863.91.
Turkish Lira Plummets; Erdogan Pledges Economic War
The lira has been under sustained pressure on foreign exchanges, dropping by nearly 50% against the dollar in the past 12 months. Turkey is now under a 25 percent tariff on imported steel and 10 percent on aluminum, which went into effect in March.
Browns kick off preseason against Giants
However, in his second series on the field, Mayfield connected with tight end David Njoku for a short touchdown pass. On the first drive Thursday night against the Cleveland Browns , Barkley also ran for a two-yard loss.
National Football League preseason quickly claims promising Redskins rookie
The Athletic and ESPN reported Brady expected his pending contract adjustment to be in place before Week 1 of the regular season. But there are other running backs, such as Ronnie Brown and Edgerrin James, who were never the same after the injury.
Seven of the 11 major S&P sectors were lower.
The Dow is up 593.92 points, or 2.4 per cent.
USA stocks closed mixed on Thursday as investors digested a batch of key economic data and corporate earnings reports.
Shares of Norwegian Cruise Line rose more than 4 percent, but Booking Holdings fell after issuing a weak third-quarter profit forecast. "You have banks losing because the 10-year U.S. Treasury (yield) came down".
The S&P 500 posted 26 new 52-week highs and three new lows; the Nasdaq Composite recorded 97 new highs and 68 new lows.
Declining issues outnumbered advancing ones on the NYSE by a 2.12-to-1 ratio; on Nasdaq, a 1.47-to-1 ratio favored decliners.