Wall Street finished a choppy session slightly lower on Tuesday as investors assessed mixed earnings reports while monitoring the fast-changing US presidential contest.

Lockheed Martin, Spotify and Sherwin-Williams rallied, while General Motors and UPS both fell on a busy day of second-quarter corporate results.

Briefing.com said of the overall muted market reaction that there was "not a lot of conviction" after Monday's solid rally.

The Dow Jones Industrial Average ended down 0.1 percent at 40,358.09.

The S&P 500 declined 0.2 percent to 5,555.71, and the Nasdaq Composite Index dipped 0.1 percent to 17,997.35.

Less than two days after President Joe Biden pulled out of the November election, Vice President Kamala Harris hit the campaign trail in the battleground state of Wisconsin as she continued to lock up major endorsements from Democratic officials.

Analysts expect the stock market to monitor the race more intensely closer to the November election date.

Among individual companies, UPS sank more than 12.1 percent as it reported lower profits and revenues and cut some annual projections.

GM dropped 6.4 percent despite reporting profits that topped estimates. Analysts noted that the automaker had seen shares appreciate significantly heading into the report and also pointed to weakness in its China business.

But Spotify jumped 12 percent as it announced that it added seven million paid subscribers in the second quarter, beating forecasts after it raised prices. (AFP)