Eli and Edythe Broad.
Eli and Edythe Broad.

KB Home's Eli Broad built the company into a Fortune 500, billion-dollar enterprise, and did the same for SunAmerica. The 83-year-old has been estimated to have a net worth of $7.3 billion. So how did he do it?

According to an article from Yahoo Finance, Broad told CNBC that unconventional thinking could be profitable, ""whether it was in home building [or] whether it was taking a life insurance company and making it a retirement-savings company."

In the late 1950s, after spending the beginning of his career as an accountant, Broad decided to borrow $25,000 from his in-laws to start the home-building company Kaufman & Broad, which is now KB Home. It went public in the 1960s and was the first in its industry to list on the New York Stock Exchange.

Since the beginning, Broad wasn't afraid to challenge the status quo. While many home builders at the time were focusing on basements, Broad went the other way and started constructing houses without them — and then selling them for 20% less than his competitors. His company also was one of the first in the industry in 1967 to offer a five-year limited home warranty.

"People who just accept the status quo and conventional wisdom don't make a difference in the world," Broad said. "It's those that challenge [it] and do things differently who advance."

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