Brian Thompson, the CEO of UnitedHealthcare's insurance unit, was fatally shot in the chest on Wednesday morning in New York City, according to multiple news sources. Thompson was attending an investor event in Manhattan that had just kicked off.

"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 Group CEO Andrew Witty said.

The NYPD deputy commissioner's office said a man was shot in front of the Hilton, located at 1335 6th Avenue in the Midtown North Precinct. He was brought to Mount Sinai West Hospital less than a mile away in critical condition and was later pronounced dead.

The shooter may be a white male wearing a black face mask, carrying a gray backpack.

Investigators said that the gunman was waiting in the area for some time before Thompson's arrival. There have been no arrests, and the investigation is active and ongoing. 

Thompson, aged 50, was named a UnitedHealthcare CEO in April 2021, and started at the company in 2004. He served as CEO of Medicare and Retirement for UnitedHealthcare, prior to his current role. 

UnitedHealthcare is a unit of UnitedHealth Group. The organization is number 5 on the Fortune 500 list, employing over 100,000 individuals.