Thompson was killed in what investigators called a targeted shooting outside a Manhattan hotel, where the health insurer was holding an investor conference.
Paulette Thompson, his wife, wrote in a statement to ABC News, "We are shattered to hear about the senseless killing of our beloved Brian. Brian was an incredibly loving, generous, talented man who truly lived life to the fullest and touched so many lives. Most importantly, Brian was an incredibly loving father to our two sons and will be greatly missed. We appreciate your well wishes and request complete privacy as our family moves through this difficult time."
"We are just so sad right now," Elena Reveiz, the sister of Thompson's wife, told ABC News by phone.
Reveiz said she was especially worried about Thompson's two children and called the CEO a good father.
One of Thompson's sons recently graduated from high school where he lettered three years on the lacrosse team, one of his coaches told the Minnesota Star-Tribune. His younger son is also an athlete.
Thompson and his wife "were present around all of the team events," assistant coach Brandon Carlson told the newspaper.
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UnitedHealthcare's parent company, UnitedHealth Group, the largest health insurer in the world, said in a statement, "We are deeply saddened and shocked at the passing of our dear friend and colleague Brian Thompson."
UnitedHealthcare is the largest provider of Medicare Advantage plans in the U.S. and manages health insurance coverage for employers and state-and federally funded Medicaid programs.
Thompson, who was 50, had run the insurance arm of health care giant UnitedHealth Group Inc. since 2021 and had worked at the company for 20 years.
As CEO, Thompson led a business that provides health coverage for more than 49 million Americans. United is the largest provider of Medicare Advantage plans, the privately run versions of the U.S. government's Medicare program for people age 65 and older. The company also sells individual insurance and administers health insurance coverage for thousands of employers and state-and federally funded Medicaid programs.
The portfolio Thompson managed generated $74 billion in revenue in the most recent quarter, making it the largest subsidiary of Minnetonka, Minnesota-based UnitedHealth Group. His $10.2 million annual compensation package, including salary, bonus and stock options awards, made him one of the company's highest-paid executives.
The University of Iowa graduate who began his career as a certified public accountant had little name recognition beyond the industry. Even to investors who own its stock, the public face of the parent company belonged to CEO Andrew Witty, a knighted British triathlete who has testified before Congress.
Thompson held several roles since joining the company in 2004, according to his LinkedIn profile.
The deadly shooting drew reaction from political leaders in Minnesota, including Gov. Tim Walz who tweeted that the state is "sending our prayers to Brian's family and the UnitedHealthcare team."