In brief: Apple CEO Tim Cook now has a net worth north of $1 billion, putting him in the rather exclusive "10-figure net worth club." But for Cook, the accomplishment is even more improbable considering he didn't found the company he runs.

Bloomberg estimated Cook's net worth based on regulatory filings and "applying the market performance of a typical wealthy investor to his proceeds from share sales." Most of his estimated wealth came as a result of equity awards earned during his career at Apple, which started way back in 1988 when he joined the company as senior vice president of worldwide operations.

Cook took over as CEO on August 24, 2011, as Steve Jobs stepped down due to health issues. Roughly six weeks later, on October 5, 2011, Jobs died from complications of pancreatic cancer.

Despite the odds, Cook has managed to push Apple to new heights. The company was worth around $350 billion when Jobs died in 2011. Today, it is approaching a $2 trillion market cap.

Even with an estimated net worth of over $1 billion, Cook isn't wealthy enough to break into the top 500 of the Bloomberg Billionaires Index. The least wealthy person on the list has an estimated net worth of $4.51 billion. On the opposite end of the spectrum, you've got Amazon founder Jeff Bezos at number one with an estimated net worth of $186 billion. Microsoft co-founder Bill Gates is second at $121 billion followed by Facebook founder Mark Zuckerberg at $99.7 billion.

In 2015, Cook said he planned to give away most of his fortune to charity.

Image credit: Laura Hutton, Novikov Aleksey