In light of the killing of UnitedHealthcare CEO Brian Thompson on Wednesday, companies may be taking a closer look at their top executives’ security measures. Thompson reportedly had an in-house security detail, CNN noted, but he was alone when a lone gunman shot him outside a Midtown Manhattan hotel.

While UnitedHealthcare’s parent company, UnitedHealth Group, doesn’t break out the security costs associated with protecting its top executives, it’s common for companies to pay millions to defend their chief executives. In recent years, companies have put more money toward security, especially for those with high-profile CEOs. And those measures can include everything from home monitoring to personal bodyguards to security consulting, which come at a big cost to companies, depending on the executive.

Thompson was not exactly a well-known CEO, but his wife told NBC that he had recently been threatened owing to his position as head of a health insurance company.

Bill Herzog, the CEO of Arizona-based LionHeart Security Services, told Fortune that it’s important for companies to invest in protecting their CEO, especially if they’re among the richest people in the world, like Meta’s Mark Zuckerberg and Tesla’s Elon Musk. Herzog, whose company has provided security for politicians and other high-profile individuals, said that these kinds of celebrity CEOs could especially be targeted. And if something were to happen to them, the company may be the one to take the hit financially and reputationally, he added.

“When you’re talking about somebody who’s worth millions of dollars or billions of dollars, and they are in charge of an entire company, there is a real possibility of kidnapping, there’s a real possibility of extortion, there’s a real possibility of attempts on their lives,” Herzog said. 

For round-the-clock security, a service that requires specially trained security experts and specific resources, Herzog said his company would charge $60 an hour or more, a sum that could bring the total bill to upwards of $1 million per year for two guards.

Yet some companies pay out much more than that to protect their chief executives. Here are some of the tech companies that pay the most:

Meta

Meta pays over three times as much as the next closest tech company on the list to protect its longtime CEO and founder, Mark Zuckerberg. In 2023, the company spent a total of $23.4 million for Zuckerberg’s personal security, including $9.4 million in direct security costs and another $14 million in an annual pretax allowance meant to “cover additional costs related to Mr. Zuckerberg and his family’s personal security.” 

In previous years, Meta has paid out even more to protect Zuckerberg, with the bill for his personal security exceeding $24 million and $25 million in 2022 and 2021, respectively, according to a filing with the Securities and Exchange Commission (SEC). 

Meta made these large security payments “for the company’s benefit because of the importance of Mr. Zuckerberg to Meta,” according to the filing. Zuckerberg is especially at risk because of his position, the company argues. 

“We believe that Mr. Zuckerberg’s role puts him in a unique position: He is synonymous with Meta, and as a result, negative sentiment regarding our company is directly associated with, and often transferred to, Mr. Zuckerberg,” the company wrote in the SEC filing.

Luckily, Zuckerberg is also a big aficionado of mixed martial arts.

Alphabet

Alphabet CEO Sundar Pichai talks a lot about cybersecurity, but his personal security is also top of mind for his company. In 2023, the tech giant forked over $6.8 million for Pichai’s personal security, according to a filing with the SEC.

Alphabet also pays for a company car and his use of “noncommercial aircraft,” e.g., the private jet.

Tesla

Tesla’s Elon Musk is no stranger to the limelight, and his personal security bill reflects that. Tesla paid $2.4 million in 2023 to a security company owned by Musk for security services, along with another $500,000 through February of this year, according to an SEC filing. 

The bombastic CEO’s steep security costs are apparently very necessary. In July, Musk said in a post on X that two separate people had tried to kill him in the past eight months. 

“They were arrested with guns about 20 mins drive from Tesla HQ in Texas,” Musk wrote.

After the failed assassination attempt on Donald Trump in July, Musk mulled taking his security into his own hands.

“Maybe it’s time to build that flying metal suit of armor,” Musk said in a post at the time. 

Nvidia

For one of the star CEOs of the moment, Nvidia spends comparatively less than its tech peers on CEO Jensen Huang’s security. In its fiscal 2024, the company spent about $2.2 million on residential security and consultation fees for Huang, plus hundreds of thousands on security monitoring services and car and driver services, according to a filing with the SEC. 

While Huang once said Jackie Chan would be best suited to play him in a movie, Huang definitely doesn’t have Chan’s martial arts skills. 

Apple

Although Tim Cook is not as famous as his predecessor, the iconic Steve Jobs, he’s still Apple’s most successful CEO, and the company wants him around for many years more. 

Apple paid $820,309 for expenses related to Tim Cook’s security in 2023, which, while not a pittance, was still less than the $1.6 million it paid for his private jet use.

A version of this story originally published on Fortune.com on Sept. 14, 2024.