Shark Tank, from Disney's (NYSE:DIS) ABC network, is one of the most popular shows on television -- but how the Sharks made their money may surprise you.

Now on its fifth season, Shark Tank has taken the world by storm, as people everywhere are exposed to entrepreneurs seeking financial support for their businesses. Yet ABC is one of the biggest winners in the whole showcase, as the most recent episode of Shark Tank registered 7.3 million viewers, which was 40% more than any other show on Friday. 

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Just like the businesses that walk through the doors to greet the Sharks are diverse and across a whole host of industries, so too are the ways the Sharks themselves made their money.

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Mark Cuban
While Mark is best known for his ownership of the Dallas Mavericks NBA team, Cuban actually made almost all of his money in the technology and broadcasting world. Mark's principal source of income was the fortune he amassed from the sale of to Yahoo! (NASDAQ:YHOO) for $5.7 billion in April of 1999. In addition to that, he's now the owner and chairman of HDNet, an independent TV network.

As a final source of income, Cuban also co-owns the Landmark Theater movie chain -- the largest independent theater chain in the U.S. -- as well as Magnolia Pictures and Magnolia Home Video. Cuban is worth an estimated $2.5 billion, placing him in spot No. 222 on the Forbes 400. 

Barbara Corcoran
A true self-starter, Barbara Corcoran made her fortune in the New York real estate market. After working as a waitress, she received a $1,000 loan to start her own real estate business. Corcoran sold the firm she started in 2001, 28 years after it was founded, for almost $70 million. 

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Kevin O'Leary
Next is Kevin O'Leary, who often comes across as the most ruthless on Shark Tank. O'Leary made his money after he built his education software business from the ground up, then bought out his competitors. In 1999, O'Leary unloaded his business to Mattel for $3.7 billion. He now runs his own mutual fund company based in Canada, O'Leary Funds, that principally invests in dividend paying stocks. O'Leary is estimated to now be worth more than $300 million. 

Daymond John
Jumping across from technology and real estate to fashion is Daymond John, who started fashion brand FUBU in 1992. Thanks to the help of friend LL Cool J to promote the brand, and high demand, just six years later, FUBU had revenues that topped $350 million at its peak in 1998. In total, FUBU has registered over $6 billion in sales, and some have estimated that Daymond's net worth is as high as $250 million.

Lori Greiner
The proclaimed "Queen of QVC," Lori Greiner is perhaps best known for her products, not her businesses. In fact, she has made more than 400 products in her lifetime and is actually the holder of more than 120 U.S. and international patents. Her specialty is retail home goods, and she started by designing and creating an earring organizer in the mid 1990s.

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Robert Herjavec
Lastly, there's Robert Herjavec who, like Mark and Kevin, found success in the technology world. Robert's parents were Croatian immigrants, and in the early 90s, he found himself waiting tables. Yet he started his own company BRAK systems and capitalized on the success of the 90s Internet craze. He then sold that business to AT&T for $30 million according to public records -- not $100 million as widely reported -- and then, after joining Ramp Networks as a vice-president of worldwide sales, helped negotiate its sale to Nokia for $225 million.

He is now the CEO of The Herjavec Group, which is an IT services and security firm based in Toronto and has reported annual sales of $65 million. 

All told, the Sharks certainly have expertise in wide-ranging areas, from technology and fashion to consumer goods and real estate, and much more, so it's no surprise they all seek to invest in the next big thing.