Robert Gillam made his fortune in money management. He founded McKinley Capital Management, which oversees $7 billion in assets.
Bruce Halle made his money by selling tires. He opened the Discount Tire Company.
Jim Walton is a Wal-mart heir. Jim is the youngest of founder Sam Walton's children and sits on the board.
Larry Ellison made his fortune with Oracle. He stepped down as CEO in 2014, but still calls some shots at his database-software company.
Charles Ergan made his money in satellite TV. He's the CEO of DISH Networks, and is considered one of the toughest dealmakers in the cable and satellite TV business.
Ray Dalio is a self-made billionaire, opening the world's largest hedge fund firm, Bridgewater Associates.
Robert Gore and Elizabeth Snyder's mother and father developed Gore-Tex.
Mickey Arison made his fortune with Carnival Cruises. He stepped down as CEO in 2013, but is chairman of Carnival Corporation.
Anne Cox Chambers and her family own media conglomerate Cox Enterprises.
Perre Omidyar founded EBay, and sits on the board of both EBay and PayPal.
Potatoes made Scott Simplot rich. If you have eaten at MCDonald's, you have probably tasted the Simplot family fries.
Ken Griffin made his fortune with the hedge fund firm Citadel LLC.
Medical devices made Carl Cook rich. He is the CEO of Cook Group, a company his parents began in the spare bedroom of their apartment in 1963.
Harry Stine made his fortune is agriculture. He sells his corn and soybean seed genetics to companies such as Monsanto and Syngenta.
Charles Koch shares Koch Industries with his brother, a $115 billion company. He is one of the most politically influential billionaires in the US.
B. Wayne Hughes built his fortune with Public Storage. His company has been going strong since 1972.
Tom Benson is a sports magnate. He has made his money owning the NFL Saints and the NBA Pelicans.
Bill and Susan Alfond are brother and sister. Their fortune comes from their parents company, Dexter Shoe Company.
Ted Lerner became wealthy with real estate. He started off selling homes to developers, and then built homes himself.
Abigail Johnson's fortune comes from money management. She took over as CEO of Fidelity in 2014, replacing her father.
Hank and Doug Meijer co-chair the family business, grocery store chain Meijer. Their grandfather opened the first store.
Whitney MacMillan's fortune comes from Cargill, the agriculture company his great-grandfather founded.
Leslie Lampton founded Ergon, a refining and chemicals conglomerate. The company began as a petroleum retailer with two employees.
Jack Taylor made his fortune renting cars. He founded Enterprise Rent-A-Car.
Dennis Washington is a self-made billionaire who made his money in construction and mining.
Warren Buffett made his billions with decades of smart investing, and his company Berkshire Hathaway.
Sheldon Adelson made his fortune running Las Vegas Sands, America's largest casino company.
Andrea Reimann-Ciardelli made her fortune when she sold her stake in her family's investment company. Her wealth is from consumer goods.
David Tepper made his billions in the hedge fund business, as a manager at Goldman Sachs, and with his own company Appaloosa Management.
Mack C. Chase made his fortune in the Permian Basin oilfields in Texas and New Mexico.
David Koch shares control of $115B company Koch Industries, with his brother Charles. Koch Industries has interests in oil, building materials, and dixie cups.
James Goodnight made his fortune after co-founding the business analytics software company, SAS.
Gary Tharaldson made his money by acquiring and selling hotels across the country.
Leslie Wexner made his billions in retail. He's behind the success of Victoria's Secret, Bath & Body Works, Express, and Abercrombie & Fitch.
Harold Hamm made his fortune in oil. He's the chairman and CEO of Continental Resources.
Phil Knight made his billions with Nike.
Mary Alice Dorrance Malone is a soup heiress. Her money comes from Campbell Soup, her grandfather's company.
Jonathan Nelson made his billions in private equity, founding Providence Equity Partners.
Anita Zucker's money comes from chemicals. She is the CEO of The InterTech Group, a conglomerate with interests in chemicals, commercial real estate, manufacturing and aerospace parts production.
T. Denny Sanford made his fortune owning PREMIER Bank and PREMIER Bankcard.
Thomas Frist, Jr. made his fortune in health care, founding Hospital Corp. of America with his father.
Alice Walton's money comes from Wal-mart. She hasn't taken an active role in the company like her siblings.
Jon Huntsman made his fortune with his company Huntsman Chemical.
John Abele has made his fortune in health care. He co-founded Boston Scientific, a medical device company.
Jacqueline Mars and her two brothers own Mars, the candy company that was started by their grandfather.
The richest man in the US. Bill Gates made his billions with Microsoft, and now uses the money for his philanthropic foundation.
Jim Justice, II's wealth comes from the coal business he inherited from his father.
John Menard, Jr. is a self-made billionaire, making his fortune with Menards home improvement stores.