Warren Buffett resigns as trustee of the Gates Foundation - weeks after Bill and Melinda's divorce announcement

• Warren Buffett is resigning as a trustee of the Bill & Melinda Gates Foundation.
• Buffett is stepping down weeks after the charity's eponymous founders announced their divorce.
• He also said he hit the 50% milestone in giving away over 99% of his Berkshire Hathaway "A" shares.

Warren Buffett is resigning as a trustee of the Bill & Melinda Gates Foundation, weeks after the Microsoft cofounder Bill Gates and Melinda French Gates announced their divorce.

"For years I have been a trustee - an inactive trustee at that - of only one recipient of my funds, the Bill & Melinda Gates Foundation (BMG)," the billionaire investor and Berkshire Hathaway CEO said in a statement. "I am now resigning from that post, just as I have done at all corporate boards other than Berkshire's."

"My goals are 100% in sync with those of the foundation, and my physical participation is in no way needed to achieve these goals," he added.

The Gateses' divorce has sent shock waves through the philanthropy community, raising questions about how one of the largest and most influential charitable organizations would function after the separation of its two eponymous founders.

The Wall Street Journal reported in late May that the Gates Foundation might establish a board and bring in outside directors to minimize disruption to its work.

Buffett highlighted in his statement that he'd given away half of his Berkshire "A" shares - a key milestone in his mission to donate over 99% of his wealth.

Buffett pledged in 2006 to contribute virtually all of his 474,998 "A" shares at the time to the Gates Foundation and four other foundations. Following his latest distribution of $4.1 billion of stock, he now owns 238,624 shares worth about $100 billion.

Together with Gates and French Gates, he has encouraged other billionaires to sign the "Giving Pledge" and commit to give at least 50% of their wealth to charity.

Buffett's statement revealing his resignation also reflected on the challenges of giving effectively and his own thoughts about philanthropy. The release may have been partly inspired by the intense scrutiny he's faced over the past couple of weeks after ProPublica, citing leaked tax returns, reported that he and other billionaires paid only a tiny fraction of their net worth in federal income taxes each year.

"The $41 billion of Berkshire shares I have donated to the five foundations has led to only about 40 cents of tax savings per $1,000 given," Buffett said. "That's because I have relatively little income. My wealth remains almost entirely deployed in tax-paying businesses that I own through my Berkshire stockholdings, and Berkshire regularly reinvests earnings to further grow its output, employment and earnings."

"The income I receive from other assets allows me to live as I wish," he added. "My needs are simple; what made me happy at 40 makes me happy at 90."

Buffett also reiterated his famous advice for wealthy people pondering what to do with their money when they died.

"After much observation of super-wealthy families, here's my recommendation: Leave the children enough so that they can do anything but not enough that they can do nothing," he said.