The S&P 500 ticked higher in a choppy session on Wednesday as a boost from Microsoft and optimism about another round of stimulus for the virus-stricken economy countered worries over worsening ties between the United States and China.
Tesla Inc and Microsoft Corp rose 1.2% and 0.8% in the run up to their quarterly reports due after markets close.
A largely upbeat start to the second-quarter earnings season, hopes for an eventual COVID-19 vaccine and an expected official support for the economy has brought the S&P 500 within 4% below its record February closing high.
Republicans and Democrats in Congress aim to pass a fourth coronavirus aid package before the end of the month, but they will have to overcome significant differences.
"While prospects of a new spending bill may counter some negative sentiment, the market doesn't always move in one direction," said Mike Loewengart, managing director of investment strategy at E*TRADE Financial Corp.
"The decidedly more cautious tone from the Trump administration on the coronavirus front ... coupled with rising tensions with China, there is enough out there for some investors to want to sit out for a round or two."
Earlier on Wednesday, futures had taken a hit after Washington told China to close its consulate in Houston, citing a need to protect American intellectual property and information, deepening a deterioration in bilateral relations. A source said Beijing was considering shutting down the U.S. consulate in Wuhan.
At 11:39 a.m. ET, the Dow Jones Industrial Average was up 85.53 points, or 0.32%, at 26,925.93, the S&P 500 was up 6.02 points, or 0.18%, at 3,263.32. The Nasdaq Composite was down 0.61 points, or 0.01%, at 10,679.76.
The real estate sectors rose about 1%, the most among major S&P sectors, while financials and energy underperformed.
Pfizer Inc advanced 3.3% as the drugmaker and German biotech firm BioNTech SE said they would get $1.95 billion from the U.S. government to produce and deliver 100 million doses of their COVID-19 vaccine candidate.
Hospital operator HCA Healthcare Inc surged 9.4% after reporting better-than-expected quarterly revenue. Thermo Fisher Scientific Inc jumped 1.7% after the scientific instruments maker beat second-quarter results.
Snap Inc declined 7.9% as it forecast fewer current-quarter users than estimates and said the initial lift in user growth at the start of coronavirus-led lockdowns dissipated faster than it expected.
Advancing issues outnumbered decliners by a 1.30-to-1 ratio on the NYSE. Declining issues outnumbered advancers for a 1.29-to-1 ratio on the Nasdaq.
The S&P index recorded 36 new 52-week highs and one new low, while the Nasdaq recorded 66 new highs and seven new lows.