While the average age of a Fortune 500 CEO is 57, several of the companies on the list are led by people ranging from 71 to 91. That might be extraordinary in some ways, but studies show that working longer could be the new norm. 

Around half of today’s five year olds will live to 100 by 2050, according to The New Map of Life: 100 Years to Thrive report from Stanford University. And as people live longer, they also work longer. The report predicts that most of these five-year-olds will work for 60-years, compared to the current average of 30 years of work for a 70-year-old.

These are 10 of the oldest Fortune 500 CEOs according to data provided by S&P Global Market Intelligence.

10. Stanley M. Bergman

Age: 71
Company: Henry Schein
Fortune 500 rank: 299
CEO tenure: 33.4 years, began in 1989

9. Albert Yuan Chao

Age: 71
Company: Westlake
Fortune 500 rank: 320
CEO tenure: 17.9 years, began in 2004

8. John F. Barrett

Age: 72
Company: Western & Southern Financial Group
Fortune 500 rank: 372
CEO tenure: 28.4 years, began in 1994

7. Richard C. Adkerson

Age: 74
Company: Freeport-McMoRan
Fortune 500 rank: 157
CEO tenure: 18.5 years, began in 2003

6. Stephen A. Schwarzman

Age: 74
Company: Blackstone
Fortune 500 rank: 159
CEO tenure: 15.2 years, began in 2007

5. William T. Dillard II

Age: 76
Company: Dillard’s
Fortune 500 rank: 488
CEO tenure: 24.1 years, began in 1998

4. A. James Teague

Age: 76
Company: Enterprise Products Partners
Fortune 500 rank: 89
CEO tenure: 6.4 years, began in 2015

3. Seifi Ghasemi

Age: 77
Company: Air Products & Chemicals
Fortune 500 rank: 350
CEO tenure: 7.9 years, began in 2014

2. Roger S. Penske

Age: 84
Company: Enterprise Products Partners
Fortune 500 rank: 89
CEO tenure: 23.1 years, began in 1999

1. Warren E. Buffett

Age: 91
Company: Berkshire Hathaway
Fortune 500 rank: 7
CEO tenure: 57.1 years, began in 1965