Seven of the 10 major S&P sectors were lower, with the healthcare sector's 0.5 percent fall leading the decliners.
The energy sector was down 0.17 percent, snapping a run of five straight days of gains.
The three major indexes had a positive start in November, after posting their best monthly performances in four years in October.
At 10:05 a.m. ET, the Dow Jones industrial average was up 3.41 points, or 0.02 percent, at 17,921.56.
The S&P 500 was down 1.63 points, or 0.08 percent, at 2,108.16 and the Nasdaq composite index was down 1.00 points, or 0.02 percent, at 5,144.13.
The S&P 500's record high is 2134.72, the Dow's all-time high is 18351.4 and the Nasdaq's is 5231.942. The Nasdaq 100 closing at a record high on Tuesday.
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A report showing the private sector added more jobs than expected last month gave investors some optimism about the health of the labor market ahead of Friday's nonfarm payrolls data.
"It's positive. It's a good sign. This sets the foundation and if the rest of the data are good, (the Fed) might feel compelled to raise rates in December," said Craig Dismuke, chief economist at Vining Sparks in Memphis, Tennessee.
The Federal Reserve has said it will move in December if there is sufficient evidence that the economy could sustain higher rates.
Other data on Wednesday showed that the U.S. trade deficit narrowed sharply in September to its lowest level in seven months as exports rebounded. Separate data showed the U.S. services sector grew at a faster clip in October.
Fed Chair Janet Yellen is scheduled to testify on the Fed's actions and plans for bank regulation and supervision at 10:00 a.m. ET (1400 GMT).
Tesla's shares rose 9.1 percent to $227.42 on Wednesday after the company promised to speed up production of its electric cars.
Groupon slumped 30.3 percent to $2.82 after it forecast weak fourth-quarter and 2016 revenue.
Michael Kors rose 3 percent to $40.46 after the handbag maker reported better-than-expected quarterly results.
Motorola Solutions fell 7.5 percent to $66 and was the biggest decliner on the S&P 500 after its profit forecast falls short of expectations.
Declining issues outnumbered advancing ones on the NYSE by 1,457 to 1,313. On the Nasdaq, 1,242 issues fell and 1,169 advanced.
The S&P 500 index showed 12 new 52-week highs and no new lows, while the Nasdaq recorded 35 new highs and 23 new lows.