Several new people made the cut; others were bumped down the list.
These people, who include a son of a cabdriver and a gas station attendant, worked hard to build empires from scratch, and came out with a pile of dough.
Many of them are tech founders, but some are just good, old-fashioned businessmen.
Company: Continental Resources
How it was founded: Hamm's first job was pumping gas. He bought a truck in 1965 and founded Harold Hamm Tank Truck Service the next year. He became one of the top Oklahoman oilfield fluid transporters. In 1967 he founded Continental Resources, oil and gas exploration, production company and took it public in 2007. Hamm then took gas processing firms Hiland Partners and Hiland Holdings private in 2009.
Company: Access Industries
How it was founded: Moscow native arrived penniless in U.S. in 1978; earned masters from Columbia, MBA from Harvard Business School.
Founded holding group Access Industries in 1986; later teamed with fellow titans Mikhail Fridman and Viktor Vekselberg to create hulking Russian oil company TNK-BP through a merger of Russia's TNK and British Petroleum. Now Russia's third largest oil firm, it is his biggest holding; firm is reportedly considering picking up BP's assets.
Company: Renaissance Technologies
How it was founded: Simons started his career as a theoretical mathematician. He taught at Harvard and broke codes for the U.S. Department of defence during the Vietnam War. He founded the hedge fund Renaissance Technologies in 1982, which uses computer modelling to find inefficiencies in highly liquid securities.
Company: MacAndrews & Forbes Holdings Inc.
How it was founded: Perelman began his career as an investor and financier in 1978 with the purchase of a stake in retail jewelry store chain Cohen-Hatfield Industries. He founded MacAndrews & Forbes Holdings in 1984.
Company: Irvine & Co.
How he became the owner: Bren started his business career in 1958 by founding the Bren Company, which built homes in Orange County. In 1963, he formed the Mission Viejo Company and began planning the development of the 11,000-acre community of Mission Viejo in Orange County.
He joined other investors to buy the 145-year-old real estate master planner and developer Irvine Co. for $337 million in 1977. He eventually purchased 92% of the firm's shares, thus becoming the firm's principal shareholder.
How it was founded: Former U. of Oregon track star founded sneaker-maker Blue Ribbon Sports in 1964. He later sold Japanese running shoes from the trunk of his car and earned extra income teaching accounting at Portland State. He renamed his footwear maker Nike, after Greek goddess of Victory, 1971.
How it was founded: After one year at Harvard, Zuckerberg dropped out and moved to the West Coast to make the social network he created in his dorm a full-fledged business.
Company: Soros Fund Management
How it was founded: Soros is Chairman of the Soros Fund Management, which he founded in 1970 with his partner, Jim Rogers. Soros is known as 'the Man Who Broke the Bank of England' after he made a reported $1 billion during the 1992 Black Wednesday UK currency crises.
How it was founded: Bezos started his career on Wall Street doing computer science. Amazon.com was the result of a cross-country road trip in 1994. Bezos wrote the business plan while driving from New York to Seattle and set up the original shop in his garage.
How it was founded: Bloomberg owns an 88% stake in Bloomberg LP, the data analytics firm he founded in 1982 after being fired from Salomon Brothers ('Living well is the best revenge,' he recently said of his multi-billion dollar turnaround).
Company: Las Vegas Sands (casinos)
How it was founded: A cabdriver's son, Adelson borrowed $200 from his uncle to sell newspapers at age 12. He later created the computer industry's marquee event, Comdex in the mid-1980s, which he sold to Japan's Softbank for $862 million 1995.
Adelson then built the $1.5 billion all-suites Venetian Resort Hotel Casino and the 1.2-million-square-foot Sands Convention centre in 1997. He opened $1.9 billion Palazzo resort in 2008.
How it was founded: Ellison founded Oracle in 1977 with $1,400 from his savings. The company was first named Software Development Laboratories (SDL). In 1979, the company was renamed Relational Software Inc., later renamed Oracle after the flagship product Oracle database.
How it was founded: A January 1975 issue of Popular Electronics inspired Bill Gates and Paul Allen. It featured Micro Instrumentation and Telemetry Systems's (MITS) Altair 8800 microcomputer. Allen noticed that they could program a BASIC interpreter for the device.
The pair worked together on it and demonstrated their program flawlessly to MITS, who then agreed to distribute it as the Altair BASIC. Microsoft was established after that, with Gates as the CEO.
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