Who was UnitedHealthcare CEO Brian Thompson?

Brian Thompson, a top executive at the world's largest health insurer, was shot and killed in front of a Midtown Manhattan hotel early Wednesday morning, the New York City Police Department said.

Thompson, 50, the CEO of UnitedHealthcare, appears to have been targeted but police said they do not have a motive. Thompson was in New York City for the UnitedHealthcare investors conference and his schedule was widely known, police said.

The masked gunman, who remains on the loose, appeared to be lying in wait and shot Thompson several times, according to police.

Thompson was a longtime executive whose rise at the company came after a stint as a business advisor at global consulting giant PwC, according to his LinkedIn page.

He lived in a non-gated neighborhood in Maple Grove, Minnesota, a Twin Cities suburb, roughly 15 miles away from UnitedHealth Group’s Minnetonka headquarters.

Before his nearly three-decade career in business, Thompson was a valedictorian during his senior year at the University of Iowa, where he earned an accounting degree, the LinkedIn page says.

Thompson led the health insurance division at parent company UnitedHealth Group, a $370 billion insurance giant that ranks #8 in the Fortune 500.

After occupying various executive roles at the company for nearly 20 years, Thompson was appointed to his current position in 2021.

Thompson's wife, Paulette Thompson, said in a statement that she's "shattered" by the "senseless killing."

"Brian was an incredibly loving, generous, talented man who truly lived life to the fullest and touched so many lives," she said. "Most importantly, Brian was an incredibly loving father to our two sons and will be greatly missed."

In response to ABC News' request for comment, UnitedHealth Group pointed to a statement: "We are deeply saddened and shocked at the passing of our dear friend and colleague Brian Thompson."

"Brian was a highly respected colleague and friend to all who worked with him," the company said. "We are working closely with the New York Police Department and ask for your patience and understanding during this difficult time. Our hearts go out to Brian’s family and all who were close to him."

Thompson's employer has been under public scrutiny this year over fallout from a lawsuit brought by shareholders and a high-profile data leak.

In May, some UnitedHealth Group stockholders filed a class-action lawsuit against the company and its top executives, including Thompson.

The lawsuit alleges UnitedHealth Group and its leadership misrepresented company practices that became the focus of a reopened Department of Justice investigation into the company.

The investigation centered on the company’s separation between different segments of its business after the acquisition of health payment processing company Change Healthcare.

The reopened probe came to light in a Wall Street Journal article in February. As a result of the disclosure, the company’s stock price declined by $27 per share, which amounted to almost $25 billion in shareholder value, the lawsuit said.

Over a four-month period before the article’s publication, Thompson sold personal shares of UnitedHealth Group worth more than $15 million, the lawsuit alleged.

UnitedHealth Group and the other defendants have not issued a formal response to the lawsuit. Plaintiffs filed an amended complaint last week and a proposed order calling on the defendants to respond by Dec. 23.

UnitedHealth Group did not directly respond to ABC News' request for comment about the lawsuit.

The company's acquisition of Change Healthcare drew renewed attention in late February after Change Healthcare suffered a ransomware attack. The ensuing data leak compromised the healthcare information of one-third of U.S. individuals, according to Congressional testimony of UnitedHealth Group CEO Andrew Witty in May.

By mid-March, the company had restored Change Healthcare’s electronic payments platform and was proceeding with payer implementations, UnitedHealth Group said in a statement that month. To assist care providers whose finances have been disrupted by the cyberattack, the company had advanced more than $2 billion through multiple channels, the statement added.

Despite public scrutiny, the company’s stock price has soared 16% this year, though it has lagged behind a 27% surge in the S&P 500.

UnitedHealth Group reported about $100 billion in revenue over a three-month period ending in September, which marked a 9% increase compared to the same timeframe a year prior, according to the company’s latest earnings report.

Soon after the earnings release in October, Thompson spoke on a conference call with investors and touted the company's performance.

ABC News' Aaron Katersky, Emily Shapiro, Miles Cohen, Jared Kofsky, Hannah Prince, Peter Charalambous and Josh Margolin contributed to this report.