Even though Brian Thompson led one of the biggest health insurers in the US, he was largely unknown to the millions of people affected by his decision-making. Wednesday's fatal shooting of the United Healthcare CEO on a midtown Manhattan sidewalk - which police call a targeted killing - thrust the executive and his business into the spotlight.

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 US government's Medicare programme 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 programmes.