The S&P 500 index fell 0.2% to 3,283.15 after gaining as much as 0.2% earlier.
UnitedHealth Group Inc, the largest US health insurer, rose 2.8% as it affirmed its full-year outlook for 2020 adjusted earnings.
The Canadian dollar traded for 76.64 cents USA compared with an average of 76.56 cents United States on Tuesday.
Britain's FTSE 100 edged 0.1% higher to 7,632, while the CAC 40 in Paris was down 0.2% at 6,028. The S&P 500 opened lower by 0.88 points, or 0.03 per cent, at 3,282.27.
"We're seeing a mixed bag of results from big banks to start earnings season with JPM and Citi coming in very strong but Wells missing expectations", wrote Mike Loewengart, vice president of investment strategy at E-Trade. The Nasdaq composite, which is heavily weighted with technology stocks, climbed 95.07 points, or 1%, to 9,273.93.
Analysts welcomed Washington's move to drop its accusation that China manipulates its currency ahead of the expected signing of a "phase one" trade deal tomorrow. Traders were spooked by a report that US tariffs would remain in place on Chinese goods even after a preliminary deal is signed Wednesday.
Goldman Sachs gained 1.2%, and Cisco Systems rose 0.7%, to lead the Dow higher.
USA stocks finished mixed on Tuesday on volatile trading as doubts arose about tariffs on Chinese imports to the US and on a mixed bag of big bank earnings.
Bank of America shares fell 1.8% after the second-largest USA bank by assets said its profit dropped in the fourth quarter. In South Korea, the Kospi slipped 0.4% to 2,230.98. Shares also fell in Taiwan and in Southeast Asia.
Traders bid up shares in Hexcel 9.6% after the company said it is being bought by rival Woodward in a deal that will create one of the largest suppliers in the aerospace and defense industry.
The modest trade pact that President Donald Trump and China's main negotiator, Liu He, have to sign eases some sanctions against China.
Yields on 10-year German bunds rose to -0.19%, while yields on the German two-year government bond hit a nine-month high ahead of the signing of the U.S. The deal is expected to lower some of the tariffs, as well as increasing Chinese purchases of USA agricultural products.
Wall Street expects S&P 500 companies' corporate earnings to decrease 2% in the last three months of 2019. That would be the first time the revenue for the S&P 500 would have fallen four consecutive quarters since the end of 2016, according to FactSet.
In other trading, benchmark crude oil rose 5 cents to $58.28 a barrel in electronic trading on the New York Mercantile Exchange. It rose 15 cents to $ 58.23 a barrel on Tuesday.
Brent crude oil, the worldwide standard, gained 1 cent to $64.50 per barrel. It gained 29 cents on Tuesday to $64.49 a barrel.
Gold rebounded, gaining $8.00 to $1,552.60 per ounce.
CURRENCIES: The dollar rose to 110.10 Japanese yen from 109.93 yen on Monday. The euro strengthened to $1.1138 from $1.1122.