Tyson Foods, Tesla and Live Nation sink; Humana climbs

Stocks that moved substantially or traded heavily Monday:

Humana Inc., up $11.87 to $280.70

Reports said the health insurer is in talks about a sale or partnership with Walmart.

Tyson Foods Inc., down $4.55 to $68.64

The Chinese government said it will place a tariff on some U.S. products, including pork.

Tesla Inc., down $13.65 to $252.48

The electric car maker said semi-autonomous mode was engaged when one of its cars was involved in a fatal crash last week.

Live Nation Entertainment Inc., down $3.97 to $38.17

The New York Times reported that the Justice Department is probing the concert-promotion and event-ticketing company.

Commvault Systems Inc., up $6.20 to $63.40

Activist investment firm Elliott Management disclosed a 7.4 percent stake in the security firm.

Exxon Mobil Corp., down $1.39 to $73.22

Energy companies slumped with oil prices Monday.

Cisco Systems Inc., down $1.88 to $41.01

Big technology companies and other recent winners declined Monday as investors continued to worry about rising trade tensions.

UnitedHealth Group Inc., up $3.20 to $217.20

The health insurer said it will work with several other companies to see if blockchain technology can reduce their costs and improve their data.