Warren Buffett is stepping down from the board of the , he said Wednesday. The Berkshire Hathaway chairman's move comes during a period of uncertainty for philanthropic organization, after the Gateses announced last month that .
"For years I have been a trustee -- an inactive trustee at that -- of only one recipient of my funds, the Bill & Melinda Gates Foundation. I am now resigning from that post, just as I have done at all corporate boards other than Berkshire's," Buffett said in a statement.
The 90-year-old billionaire praised foundation CEO Mark Suzman and said his goals remained "100% in sync with those of the foundation," but noted that his physical participation isn't needed to achieve them.
In a statement, Melinda Gates expressed gratitude for Buffett's generosity and leadership, saying "the things we've learned from him will continue to help us chart a way forward." Bill Gates added that Buffett "will continue to inspire our foundation as we work to fight poverty and help millions of people live healthier lives."
Bill Gates and Buffett are the fourth and eighth richest people in the world, according to the Bloomberg Billionaires Index, with net worths of $145 billion and $105 billion, respectively. Buffett also said on Wednesday that he's given away $4.1 billion worth of Berkshire Hathaway shares following his 2006 pledge to donate 99% of his fortune.