Late-blooming billionaires

David Duffield founded PeopleSoft, the company that would put him on the Forbes map, in 1987 at the age of 47. His fourth startup, he mortgaged his house to fund it, but he says he wasn't nervous: "You kind of know when you're on to something."

He sure was: PeopleSoft became the world's second-largest application software company before it was acquired by Oracle in 2005, and Duffield vaulted onto the Forbes 400, with a fortune estimated this year at $1.2 billion.

Young-gun billionaires like Mark Zuckerberg and Sergey Brin have captured the public's attention with their meteoric success, but fortune-building is by no means the preserve of the youthful and brilliant. Many have soared into billionaire-dom later in life after changing careers, bouncing back from losses or making crucial connections. For the past eight years, the average age of new members to the Forbes 400 and Billionaires lists is 54.

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Before building PeopleSoft Duffield says he hadn't nailed down the right management style or company ethos, which he came to believe was a focus on customer service and a team atmosphere where employees believe they're valued and "work together in a global spirit." Of his prior businesses, he says, "Frankly, [they] didn't work. [Success] came with time. I made a lot of mistakes along the way."

John Sperling had a wild idea in his 50s that ended up making him wealthy. A humanities professor at San Jose State University, his life changed in 1972 when he was assigned to run a federally funded series of classes to help police and schoolteachers work with juvenile offenders. Sperling was struck by how eager the adults in the program were to further their educations, which they had limited opportunities to do.

Image: Sheldon Adelson

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