Only these 2 CEOs make Zuckerberg look poor

Mark Zuckerberg plans to give away 99% of his $45 billion fortune in Facebook (FB) - probably figuring he'll still be fabulously wealthy. He's right - but it's amazing how right he is.

Just two current CEOs of companies in the Standard & Poor's 500, Warren Buffett of Berkshire Hathaway (BRK.A) and Jeffrey Bezos of Amazon.com (AMZN), hold shares in their companies worth more than Zuckerberg's stake in Facebook, according to a USA TODAY analysis of data from S&P Capital IQ. Buffett and Bezos' stakes are valued at $61.7 billion and $56.2 billion, respectively, according to a USA TODAY analysis of data from S&P Capital IQ.

That's not to belittle the move by Zuckerberg, who this week showed off photos of his new baby, a big life-changing event that sparked all the talk about his fortune's future. Here are some numbers to put the vast size of Zuckerberg's fortune into perspective - even among the ranks of CEOs:

* Zuckerberg is already a titan. Zuckerberg's ownership in Facebook alone account for 17% of all the value current CEOs hold in their own companies' shares, based on S&P Capital IQ data.

Money Sharma | AFP | Getty Images

Facebook founder and Chief Executive Mark Zuckerberg.

* Even 1% of Zuckerberg's wealth is still staggering. Even after giving away 99% of his Facebook holdings, Zuckerberg's remaining stake is worth $453.9 million. That remaining 1% stake is larger than all but 24 of CEOs total stakes in their companies among the S&P 500. Zuckerberg's stake is also just below the average $536.6 million position held by the current CEOs that have reported their holdings.

* Zuckerberg's big ownership has paid off. Facebook's might be worth 44% less than its chief rival, Alphabet. But Zuckerberg has maintained a 15% stake in Facebook, while Alphabet's Larry Page has just a 6.3% stake in Alphabet. That means Zuckerberg's holding in Facebook worth much more than Page's $33.3 billion stake in Alphabet.

* Wealth is concentrated - even in the CEO world. Just four CEOs, Buffett, Bezos, Zuckerberg and Page have holdings in their companies worth $30 billion or more. CEOs' holdings drop off after that. The median holding of S&P 500 CEOs in their company stock, or the midpoint between the highest and the lowest stakes, is $17.8 million.

Zuckerberg certainly has lofty goals for the money he's giving away: It's a fortune that puts him among the CEO legends.

S&P 500 CEOS WITH THE MOST VALUABLE STAKES IN THEIR COMPANIES

CEO, Company, Symbol, Value of CEO holdings ($ bils.)

Warren Buffett, Berkshire Hathaway, BRK.A, $61.7

Jeffrey Bezos, Amazon.com, AMZN, $56.2

Mark Zuckerberg, Facebook, FB, $45.4

Lawrence Page, Alphabet, GOOGL, $33.3

Stefano Pessina, Walgreens Boots Alliance, WBA, $17.9

Kevin Plank, Under Armour, UA, $3.1

Marc Benioff, salesforce.com, CRM, $3.0

Frederick Smith, FedEx, FDX, $2.9

Howard Schultz, Starbucks, SBUX, $2.4

Leslie Wexner, L Brands, LB, $2.3

Source: S&P Captial IQ based on most recently reported common equivalent shares, USA TODAY research