At the closing bell, the Dow Jones Industrial Average gained 19.30 points (0.11 percent) to 16,975.37, while the broad-based S&P 500 added 1.23 (0.06 percent) at 1,974.55. Both notched records for the second day in a row.
The tech-rich Nasdaq Composite Index slipped 0.92 (0.02 percent) to 4,457.73.
Payrolls company ADP said the private sector added 281,000 jobs in June, surging higher from 179,000 in May. That came ahead of Thursday's Department of Labor report on job creation and unemployment nationwide in June.
Dan Greenhaus, chief global strategist for BTIG, said Thursday's trade could be volatile due to the jobs report and the abbreviated period for placing trades. Markets close at 1700 GMT Thursday, there hours ahead of usual due to the US Independence Day holiday.