Warren Buffett’s gifts to Bill Gates’ foundation are worth…

Microsoft co-founder Bill Gates with Berkshire Hathaway CEO Warren Buffett.

The Bill & Melinda Gates Foundation has several high-profile donors but there is one who has been particularly generous -- veteran investor Warren Buffett.

Bill Gates has said that though the charity is named after him and his former wife, Warren Buffett's contributions are what make up for half of its resources.

In a blog last week, the Microsoft co-founder said that Buffett has donated $35.7 billion to his foundation since 2006. The latest donation, worth $3.1 billion, came in June.

Gates said the real value of Buffett's gifts was higher.

"$45 billion if you include the appreciation of the Berkshire Hathaway stock after it was given," the billionaire philanthropist added.

But it was not just Buffett's donations that shaped the foundation, Gates remarked.

"Warren’s advice and thinking influenced the foundation in a profound way even before he made any gifts," he added. "Warren, I can never adequately express how much I appreciate your friendship and guidance as well as your generosity."

Gates had announced last week his foundation will increase its annual spending to $9 billion per year by 2026, up from $6 billion in pre-coronavirus times. For that purpose, the tech boss said, he will transfer $20 billion to charity.

The Microsoft co-founder added that it was a necessary step, considering the coronavirus pandemic, the climate crisis and the Russia-Ukraine war.

Gates revealed his plans to give all his wealth, other than what he spent on himself and his family, to the foundation.

“I will move down and eventually off of the list of the world’s richest people,” he wrote in the blog. “My giving this money is not a sacrifice at all. I feel privileged to be involved in tackling these great challenges, I enjoy the work, and I believe I have an obligation to return my resources to society in ways that have the greatest impact for improving lives.”