UnitedHealthcare CEO Brian Thompson, 50, was fatally shot Wednesday morning in midtown Manhattan as a company shareholder meeting began. Here are answers to some frequently asked questions about Thompson and UnitedHealthcare.

Minnetonka-based UnitedHealth Group (UNH) is a diversified, traded healthcare company with more than 400,000 employees. It includes UnitedHealthcare, the country’s largest health insurer. UNH was recently ranked in the top 5 of the Fortune 500 list of American companies, just behind Apple, and is publicly traded on the New York Stock Exchange. The company is Minnesota’s 10th largest employer and employs approximately 19,000 workers in the state.

UnitedHealthcare (UHC), a division of UNH, is the largest provider of health insurance products in the United States. It provides private health insurance to more than 52 million people, including 29 million with private or corporate health insurance and more than 20 million people with government-subsidized Medicare and Medicaid plans.

Thompson was named chief executive officer of UnitedHealthcare in April 2021 after joining UNH in 2004 and holding various leadership positions within the company. He led UnitedHealthcare’s Medicare business for several years. According to his company bio, the University of Iowa graduate previously worked as an auditor at PricewaterhouseCoopers. He lived in Maple Grove. Thompson was fatally shot Dec. 4 outside a New York City hotel ahead of a planned annual investor conference.

Optum is another well-known division of UNH, providing direct healthcare and pharmacy services as well as data analysis on healthcare trends. Approximately 90,000 physicians are employed by or affiliated with Optum, the largest such number in the United States. Approximately 40,000 advanced practice nurses are also employed by or affiliated with Optum.

The company’s insurance department has been heavily criticized in the press and by elected officials for the way it reviews and denies applications or claims for medical care. UnitedHealthcare has been investigated for its use of prior authorization to determine whether services to seniors covered by Medicare Advantage plans are medically necessary. The U.S. Senate Permanent Subcommittee on Investigations announced in October that UnitedHealthcare, along with the other two largest Medicare Advantage insurers, Humana and CVS, boosted profits by denying seniors stay in post-acute care facilities while they recovered from injuries and illnesses. According to the subcommittee’s report, UnitedHealthcare’s prior authorization denials rate for post-acute care rose from 10.9% in 2020 to 22.7% in 2022. The denials, the subcommittee wrote in its report, “can force seniors to making difficult decisions about their health and finances in the uncertain days after leaving a hospital.”

A cyberattack earlier this year on another UNH affiliate, Change Healthcare, affected 100 million patients, making it one of the largest data breaches in U.S. history. Optum acquired Change in 2022 for $13 billion. The department processed about 15 billion healthcare transactions per year before the attack. Some healthcare providers reported months-long delays in paying claims following the cyberattack.

The demonstrations outside the UNH headquarters in Minnetonka have grown larger and attracted more attention. Eleven people were reportedly arrested on July 15 when the People’s Action Institute protested the company’s refusal to approve or pay for care. A former Republican state representative, Jenn Coffey, led the protest after funds to pay for cancer treatment ran out and she clashed with UnitedHealthcare over its denials and coverage limits.