The Dow Jones Industrial Average dropped 39.11 points, or 0.11 percent, to 35,360.73. The S&P 500 fell 6.11 points, or 0.13 percent, to 4,522.68. The Nasdaq Composite Index lost 6.65 points, or 0.04 percent, to 15,259.24.
Seven of the 11 primary S&P 500 sectors ended in red, with energy and technology down 0.73 percent and 0.56 percent, respectively, leading the laggards. Real estate rose 0.62 percent, the best-performing group.
Despite Tuesday's slide, U.S. equities closed out August with gains. For the month, the Dow added 1.2 percent, while the S&P 500 and the tech-heavy Nasdaq advanced 2.9 percent and 4 percent, respectively.
U.S.-listed Chinese companies traded higher on Tuesday, with all the top 10 stocks by weight in the S&P U.S. Listed China 50 index ending the day on an upbeat note.
On the economic front, a report showed U.S. consumer confidence sank in August to a six-month low.
The U.S. Consumer Confidence Index fell to 113.8 in August from the July reading of 125.1, New York-based The Conference Board reported on Tuesday.
"Consumer confidence retreated in August to its lowest level since February 2021 (95.2)," said Lynn Franco, senior director of Economic Indicators at The Conference Board.
"Concerns about the Delta variant - and, to a lesser degree, rising gas and food prices - resulted in a less favorable view of current economic conditions and short-term growth prospects," Franco said.
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