Warren Buffett just donated about $5 billion of Berkshire Hathaway shares - and has now given up 54% of his stockpile

• Warren Buffett gifted close to $5 billion in stock to philanthropic groups on Wednesday.
• The famed investor has donated about 54% of his Berkshire Hathaway stock in recent years.

Warren Buffett gifted about $5 billion worth of Berkshire Hathaway stock to philanthropic groups on Wednesday. Tally up the shares he's given away over the past 17 years, and they would be worth an astounding $132 billion today.

The renowned investor and Berkshire CEO said in a press release that he converted roughly 9,100 of his Berkshire "A" shares into 13.7 million "B" shares, worth $4.6 billion as of Wednesday close.

He gave about 10.5 million of those shares to the Bill & Melinda Gates Foundation, just over 1 million shares to the Susan Thompson Buffett Foundation, and about 732,000 shares to each of the Sherwood Foundation, Howard G. Buffett Foundation, and Novo Foundation.

Buffett is close friends with Bill Gates and the biggest financial backer of the Microsoft cofounder's foundation, which focuses on fighting poverty, disease, and inequity worldwide. The Susan Thompson Buffett Foundation is named after Buffett's late wife, while Buffett's three children each run one of the other three foundations.

Buffett owned 474,998 "A" shares in 2006, when he decided to begin making yearly donations to good causes. He's gifted the equivalent of 257,000 "A" shares since then, leaving him with about 219,000 shares. Buffett's original crop of shares was worth $43 billion, and he hasn't bought or sold a Berkshire share since.

Berkshire's stock price has climbed in recent years, lifting the value of Buffett's stake. As a result, the shares he's donated over time are worth about $50 billion based on their value when received, or more than his entire net worth in 2006. They're worth $132 billion at Berkshire's current stock price.

Buffett's remaining shares are worth about $113 billion in total, and make up the vast majority of his $118 net worth. All else being equal, if Buffett had retained all those shares, his fortune would exceed $250 billion. That figure dwarfs the $232 billion fortune of Elon Musk, the Tesla and SpaceX CEO who currently tops the Bloomberg Billionaire Index.

"The mathematics of the lifetime commitments to the five foundations are interesting," Buffett said in his press release on Wednesday, noting that he's donated more money than he originally had in 2006. He also emphasized that the scale of his giving is a product of several fundamental factors.

"Nothing extraordinary has occurred at Berkshire; a very long runway, simple and generally sound decisions, the American tailwind and compounding effects produced my current wealth," he said.

Buffett has given away 54% of his Berkshire shares so far, and has pledged that over 99% of his personal wealth will go toward good causes. He stepped up his charity efforts last year with a surprise contribution in November. He distributed "B" shares worth $759 million in total to his four family foundations, and described the move as the "ultimate endorsement" of his children by him.