Warren Buffett Made 95% of His Wealth After Age 65. Here's How Much His Net Worth Has Grown Past Retirement Age. Buffett has served as CEO of Berkshire Hathaway since 1970, marking over five decades of leadership at the company. Previous Article JPMorgan's New 'Supertall' Office Offers Perks Like High-End Restaurants and a High-Tech Gym. Here's What Else to Expect. Next Article How Social Support Protects Your Mental Health