Billionaire Warren Buffett shocked an arena full of shareholders Saturday by announcing that he will retire at the end of the year, bringing the curtain down on a six-decade run leading Berkshire Hathaway that made him the most influential investor in the world.

Buffett said he will step down as CEO of Berkshire Hathaway, ending a 60-year run where he became an influential and iconic part of the U.S. economy.

Buffett has penned dozens of shareholder letters over the decades, offering insight into his philosophy and shaping generations of investors.