Investors have also been wary about a trade war after China chose to impose extra tariffs on 128 USA products over the weekend, in retaliation to Trump's decision to impose tariffs on steel and aluminium.
In 1.49pm trading in NY, the Dow Jones Industrial Average rose 0.7 percent, while the Nasdaq Composite Index gained 0.2 percent. The S&P 500 .SPX fell 58.99 points, or 2.23 percent, to 2,581.88 and the Nasdaq Composite .IXIC dropped 193.33 points, or 2.74 percent, to 6,870.12.
The Dow moved higher as gains in shares of Nike and those of Johnson & Johnson, recently up 2.9 percent and 2.2 percent respectively, outweighed declines in shares of General Electric and those of Walt Disney, down 1.1 percent and 0.5 percent respectively.
Amazon and Tesla, the top drags yesterday, rose, with the Dow and the S&P opening above their 200-day moving averages. The index lost 3%, which is set to be its biggest one-day percentage drop since February 8, as well as its sixth daily drop of the past eight sessions. The company has lost $83 billion in market value since mid-march.
USA technology companies are in the spotlight, notably Amazon, which posted hefty losses of around 5 per cent Monday after Trump again voiced his concerns about the company on Twitter. CBS shares rose 0.9 per cent.
Trump on Monday again criticized the e-giant's tax treatment as well as its its use of the United States Postal Service, tweeting: "Only fools, or worse, are saying that our money losing Post Office makes money with Amazon".
The looming threat of tighter regulation of the tech sector in Europe and the USA prompted investors to pull money out of high-flying companies, such as Netflix, Microsoft and Alphabet, Google's parent company. Snap fell 8 percent over planned layoffs.More news: SpaceX launches used supply ship on used rocket for NASA
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Volatility was the theme in the US equity markets during the holiday-shortened week.
Tyson Foods dropped 6.2 percent after China raised tariffs on imported US goods including pork.
Despite its recent losses, Amazon stock is still up about 18 percent in 2018.
Health insurer Humana jumped 4.9 percent on continued reports Walmart might buy the company or announce a new partnership with it. Google's Alphabet, whose own data collection has come under fire in the wake of the Facebook scandal, fell 2.4 percent.
Tesla declined after the electric auto maker said Friday that the vehicle in a fatal crash last week in California was operating on Autopilot mode, making it the latest accident to involve a semi-autonomous vehicle.
The June gold contract closed up $19.60 at US$1,346.90 an ounce and the May copper contract was up two cents at US$3.05 a pound. The yield on the 10-year Treasury note fell to 2.72 percent from 2.74 percent after a sharp decline last week.
Energy companies skidded as benchmark USA crude lost $1.93, or 3 percent, to $63.01 a barrel in NY.
CURRENCIES: The dollar declined to 105.99 yen from 106.50 yen. The euro edged up to $1.2308 from $1.2306. The Hang Seng in Hong Kong was closed as well. Natural gas picked up 1 cent to $2.70 per 1,000 cubic feet.