Warren Buffett has stepped down from his trustee position at the Bill and Melinda Gates Foundation, which says it will announce plans next month to answer questions about the foundation's leadership structure.
The "Oracle of Omaha" said he will donate $4.1 billion worth of Berkshire Hathaway shares to five charity foundations, including to BMGF, after he resigns.
In a statement quoted by CNBC, the 90-year old investor said "today is a milestone for me...in 2006, I pledged to distribute all of my Berkshire Hathaway shares - more than 99% of my net worth - to philanthropy. With today's $4.1 billion distribution, I'm halfway there."
The billionaire did not explain why he is resigning. He said he has given up all directorships outside Berkshire, reducing his workload.
Founded in 2000, the Gates Foundation focuses on combating poverty, inequity and disease, spending nearly $55 billion in its first two decades.
The foundation has a trust endowment of around $50 billion and about 1,600 staff, having funded work in 135 nations.
The foundation's future has been uncertain since its namesake co-founders announced last month they were divorcing after 27 years of marriage.
Now that Buffett is leaving, Melissa Berman, the president and chief executive officer of Rockefeller Philanthropy Advisors, said it gives the foundation an opportunity to ponder on its governance for the long run.
In separate statements Wednesday, Bill and Melinda Gates said they were grateful for Buffett's leadership, generosity and friendship, according to Al Jazeera.
Buffett has in recent years quit from all other corporate boards outside of Berkshire Hathaway, but said he has no plans of stepping down from his role as Berkshire chief executive.
