The stock price of UnitedHealthcare has decreased following the death of its CEO.

• Since the deadly shooting of Brian Thompson, CEO of UnitedHealth Group's insurance arm, major insurance stocks have dropped more than 6% from their closing prices on Tuesday.
• The three largest private health insurers in the United States are UnitedHealth Group, CVS Health, and Cigna.
• Jared Holz, Mizuho's health-care equity strategist, stated that the negative rhetoric surrounding insurers and their business management seems to be affecting that stock's performance.

Since the deadly shooting of Brian Thompson, CEO of 's insurance arm, in midtown Manhattan, major insurance stocks have fallen more than 6% from their closing prices on Tuesday.

UnitedHealthcare, operated by Thompson, is the largest private payer of health insurance benefits in the U.S.

Luigi Mangione, 26, was accused of fatally shooting Thompson outside the Hilton hotel in midtown Manhattan early Wednesday last week, as the CEO headed to UnitedHealth Group's investor day. Investigators have stated that Mangione was a critic of the health-care industry, a view that some Americans sympathized with online in the days following Thompson's death.

Jared Holz, Mizuho's health-care equity strategist, stated in an interview that the stock performance of companies seems to be influenced by the "renewed rhetoric" criticizing insurers' practices, which result in profits at the expense of patients at different times of the year.

Many Americans blame the spiraling health-care costs on a theme that is not new in the industry.

Holz stated that investors' response to the renewed negative focus on the industry is, "Do we want to own this category of stocks?"

Like other major insurers, UnitedHealthcare has faced legal challenges and backlash from regulators, politicians, and patients due to allegations of denying claims to increase profits. Patients in the US have criticized insurance companies for denying coverage for services or treatments, receiving unexpected bills, paying high out-of-pocket costs, and dealing with the confusing complexity of navigating coverage.

Since the shooting, there has been a growing opposition to the industry. However, Holz believes that the negative stock reaction will only be temporary. He also stated that he does not anticipate any significant changes in insurance policies due to the killing.

Holz stated that he does not believe companies take any proactive actions differently as a result of this.

In New York, Mangione was charged with second-degree murder, criminal possession of a loaded gun, and other crimes on Monday night, following his arrest in Altoona, Pennsylvania. This came after his initial court appearance in Pennsylvania on separate gun and forgery charges.

After being arraigned Monday evening, Mangione, a private-school valedictorian and Ivy League graduate from an influential Maryland family, was held without bail.

On Tuesday afternoon in a court hearing, Mangione declined to relinquish his right to contest his extradition to New York City. As a result, a judge rejected Mangione's bail request, and he was remanded to a Pennsylvania prison.

Law enforcement officials informed NBC News that Mangione was in possession of handwritten pages that contained criticism of the U.S. health-care system and specifically targeted UnitedHealthcare at the time of his arrest.

"I am sorry for any distress caused, but it was necessary. Honestly, those pests deserved it," Mangione wrote, according to NBC.

The motive for the shooting is still being investigated, and it is expected to be revealed as the investigation continues, according to New York City Police Commissioner Jessica Tisch. She also mentioned that Mangione's note contained anti-corporatist sentiment and issues with the health care industry.