Since his disastrous debate performance in June, the calls have only grown louder for U.S. President Joe Biden, age 81 and the oldest man to run the White House, to step aside. Top Democratic leaders this week joined the rank-and-file members in calling for Biden to drop out of the race ahead of November’s election. Biden has so far insisted he is not too old to do the job—raising the question of how he compares in age to those leading the largest companies in the U.S.

Fortune has compiled a list of the seven oldest CEOs in the Fortune 500. While the average age for all Fortune 500 CEOs is 57, the age of chief executives on this list ranges from their late 70s to early 90s. All of them have been in their roles for more than 10 years or even since the company was founded. The average overall tenure of CEOs in the Fortune 500 is seven years.

Below is the list of those CEOs, ranging from oldest to (relatively) youngest.

Warren E. Buffett, 94, Berkshire Hathaway, No. 5 in the Fortune 500

Buffett has led the multi-industry conglomerate since 1965. Berkshire Hathaway’s principal business lines are in the insurance, railroad freight, and utility industries. But the company’s many subsidiaries include insurer Geico, the railway BNSF, See’s Candies, the Dairy Queen restaurant chain, running-shoe maker Brooks, battery maker Duracell, and paint manufacturer Benjamin Moore. Berkshire Hathaway also owns a substantial portfolio of equities and other investments. The company generated $364.5 billion in revenue for 2023.

Although Buffett has been at the helm of the company for more than five decades, he has selected Greg Abel, chair of Berkshire Hathaway Energy, as his successor. However, the Oracle of Omaha hasn’t yet announced when he will retire.

Roger S. Penske, 87, Penske Automotive Group, No. 146 in the Fortune 500

Since 1999, Penske has served as chair and CEO of the diversified international transportation services company and an automotive and commercial truck retailer. He has also been chair of the board and CEO of Penske Corporation since 1969 and chair of the board of Penske Truck Leasing Corporation since 1982. In 2023, the company earned $29.5 billion in revenue. Penske is also a retired auto racer, who owns the famed Indianapolis Motor Speedway and the IndyCar Series.

Robert Greenberg, 84, Skechers, U.S.A. No. 465 in the Fortune 500

Greenberg has served as Skechers’ chair and CEO since he co-founded the company in 1992. The California-based footwear company earned $8 billion in revenue in 2023. Greenberg, a Boston native with an entrepreneurial background, is also the founder of L.A. Gear and started his career as a hairstylist and a salon owner.

Skechers’ leadership is a family affair with Greenberg at the helm, and his son, Michael Greenberg, also a co-founder, serving as president. In March, the SEC announced that Skechers agreed to pay a $1.25 million civil penalty to settle charges for failing to disclose payments for the benefit of its executives and their immediate family members.

Albert H. Nahmad, 83, Watsco, No. 489 in the Fortune 500

Nahmad founded the distributor of air conditioning, heating and refrigeration equipment. He’s been leader, chairman, and CEO since 1972. Nahmad played a central role in expanding the business through acquisitions, and strategic business relationships. Watsco has grown from a market capitalization of $22 million in 1989 to $7.3 billion at the end of 2023, generating a compounded annual growth rate of total shareholder return of 19%. Watsco now serves more than 125,000 active contractor customers through a network of 690 locations.

Selfi Ghasemi, 80, Air Products & Chemicals, No. 322 in the Fortune 500

Ghasemi became chairman, president and CEO of Air Products in July 2014. The company reached $12.6 billion in revenue in 2023. “We did very well [in 2023], and I hope it will continue,” Ghasemi said during a Barclays conference in February. “But in general, I’m the glass-half-full guy, I’m very optimistic.” Before joining Air Products, he served as chairman and CEO of Rockwood Holdings, a lithium and advanced materials company. He also held leadership roles at GKN, a global industrial company, including chairman and CEO of GKN Sinter Metals, Inc. and Hoeganes Corporation. Earlier in his career, Ghasemi spent nearly 20 years with The BOC Group.

A.J. Teague, 79, co-CEO, Enterprise Product Partners, No. 90 in the Fortune 500

The natural gas and crude oil pipeline company with headquarters in Houston reached $49.7 billion in revenue in 2023. Teague has served as co-CEO since January 2020 and has been a director of Enterprise GP since 2010. Teague previously served as CEO of Enterprise GP, as well as COO and EVP, and several other leadership roles within the company. Teague joined Enterprise in connection with its purchase of certain midstream energy assets from affiliates of Shell Oil Company in 1999. He also served as president of Tejas Natural Gas Liquids, LLC, then an affiliate of Shell, and was president of marketing and Trading for MAPCO, Inc.

Stephen A. Schwarzman, 77, Blackstone, No. 464 in the Fortune 500

Schwarzman is chair, CEO, and co-founded Blackstone in 1985. It’s one of the world’s largest alternative investment firms with over $1 trillion assets under management as of March 31. The firm reached $8 billion in revenue in 2023. The firm has investing businesses across asset classes, including private equity, real estate, and credit. Blackstone also has major businesses dedicated to infrastructure and life sciences investing. Schwarzman is not a technologist but one of AI’s early backers and a proponent of the technology. He has donated about $500 million to AI education and research. This includes a $350 million gift to MIT in 2018 followed by a grant to Oxford that ultimately totaled over £190 million, equivalent to roughly $240 million.