5. Warren Buffett

Title: CEO, Berkshire Hathaway

Country: US

Age: 85

Berkshire Hathaway CEO Warren Buffett bought his first stock at age 11 and never looked back. Since then, Buffett has continued to amass a fortune of $65 billion through a near-clairvoyant knack for making smart, long-term bets on companies like Coca-Cola and American Express. His shareholder letters are a must-read for investors looking to glean his wisdom.

His company has grown exponentially since he took over in 1964: $1,000 invested in Berkshire Hathaway stock then would be worth more than $10 million today. It remains one of the titans of the business world, announcing its largest acquisition ever in August with the $37.2 billion buyout of nuts and bolts maker Precision Castparts.

Buffett is a friend of Microsoft cofounder Bill Gates, whom he collaborated with on the Giving Pledge, a promise for billionaires to give away at least 50% of their wealth to charity. Buffett has given away nearly $3 billion in each of the past two years, and $21.5 billion in his lifetime.