Berkshire Hathaway chair and CEO and Giving Pledge co-founder Warren Buffett has donated shares of the conglomerate valued at approximately $4.1 billion to five foundations and announced his resignation from the Bill & Melinda Gates Foundation board.

With his latest annual contributions to the Gates, Susan Thompson Buffett, Sherwood, Howard G. Buffett, and NoVo foundations, Buffett is halfway to the goal he announced in 2006 of giving all 474,998 of his Berkshire Hathaway "A" shares — more than 99 percent of his net worth — to philanthropy. Buffett still owns 238,624 shares, worth about $100 billion, all of which will go to philanthropy.

In a statement "to supply a bit of history and suggest a few subjects for further thought by philanthropists, government, and the public," Buffett announced that he was resigning from the board of the Gates Foundation, the only recipient foundation of which he had been a trustee. "My goals are 100 percent in sync with those of the foundation," wrote Buffett, "and my physical participation is in no way needed to achieve these goals." Bill Gates and Melinda French Gates reportedly are discussing changes to the structure of their foundation that would strengthen the organization's governance and increase the independence of its board.

In his statement Buffett emphasized how easy it has been to give away what he has accumulated through his investments and compound interest — "I've made no sacrifice nor has my family....Society has a use for my money; I don't," he wrote — and expressed admiration for people he described as the "heroes" of philanthropy: "those who give their love and time in order to directly help others — perhaps adding a monetary gift that requires them to give up the purchase of something meaningful for their own use."

Buffett also indirectly referred to the Accelerating Charitable Efforts (ACE) Act, which, as proposed, would reform tax laws and require donor advised funds to disburse assets to nonprofits within a "reasonable" timeframe and encourage account holders to accelerate their giving. While noting that the $41 billion in Berkshire shares he has donated to the five foundations has led to only about 40 cents of tax savings per $1,000 given because he has relatively little income, as opposed to wealth, Buffett admitted that "[n]evertheless, tax deductions are important to many — particularly to the super-rich — who give large amounts of cash or securities to philanthropy. It is fitting that Congress periodically revisits the tax policy for charitable contributions, particularly in respect to donors who get 'imaginative.'"