Brian Thompson, the CEO of UnitedHealth's insurance unit, was fatally shot on Wednesday morning outside a midtown Manhattan hotel, several media outlets reported, just before a scheduled company investor conference.
The New York Police Department said a man was shot in front of the Hilton on Sixth Avenue around 6:40 am ET (1140 GMT) and was pronounced dead at a nearby hospital.
The victim's identity has not been released, but several publications reported it was Thompson, who has worked at the Minnesota-based company for 20 years.
Police were still searching for the masked suspect, who fled on foot wearing a cream-coloured jacket and a gray backpack, the Times reported.
The attack appeared to be targeted, the New York Times reported, citing police. Investigators believe the gunman had been waiting in the area for some time before Thompson's arrival ahead of an investors meeting, CNN reported.
UnitedHealth Group was hosting a scheduled investor event at the Hilton on Wednesday, but Chief Executive Andrew Witty took the stage about one hour after its start to announce it was cancelling the remainder of the programme.
"We're dealing with a very serious medical situation with one of our team members, and as a result, I'm afraid we're going to have to bring to a close the event today," UnitedHealth CEO Andrew Witty said.
UnitedHealthcare is the largest US health insurer. Thompson was named its CEO in April 2021 after working at the company since 2004 in several departments, according to the company's web site.
Consumer frustration with the US healthcare system runs high and was the driving force behind the US Affordable Care Act, which created a new type of health insurance and mandated coverage for preventative care as well as maximum profit levels.
A cyberhack early in 2024 by another UnitedHealth company called Change that provided technology for most US providers affected more than one third of Americans, who had their information stolen.
Millions of providers experienced disruption in their businesses that lasted months, delaying care for patients and even salaries for healthcare employees.