Mark Zuckerberg, 28, is worth $13.3 billion. Zuckerberg made his cash after starting up Facebook.

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Scott Duncan, 30, is worth an estimated $5.1 billion. He inherited his fortune from Dan Duncan, founder of Enterprise Products Partners. He is the fourth youngest billionaire and one of two young billionaires from Houston. Photo: .

Eduardo Saverin, 30, is worth $2.2 billion. Like Dustin Moskovitz, he made his money after investing in Facebook’s early days.

Photo: Munshi Ahmed, Bloomberg

Sean Parker, 33, is worth $2 billion. Parker started Napster, and he also served as Facebook’s first president. He did all of that before turning 25.

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Jack Dorsey, 36, is worth an estimated $1.1 billion. He made most of his wealth by investing in the mobile payment company Square. Oh, he also started Twitter.

Photo: Cody Duty, Houston Chronicle

Larry Page, 39, is worth an estimated $23 billion. Page co-founded Google with Sergey Brin. 

Photo: Eric Risberg, AP

Ryan Kavanaugh, 38, is worth an estimated $1 billion. He made the Forbes billionaire list for the first time due his success with his movie studio, Relativity.

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John Arnold, 38, is worth an estimated $2.8 billion. He made his fortunes working in the hedge fund business. He is one of two young billionaires from Houston.

Photo: Dave Rossman, For The Chronicle

Dan Gertler, 39, is worth an estimated $2.2 billion. Gertler made his money by investing his family’s fortune in mining assets in the Democratic Republic of Congo.

Photo: MATI STEIN, AP

Sergey Brin, 39, is worth an estimated $22.8 billion. He made his money by co-founding Google with Larry Page.

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