On June 25, 2006, Warren Buffett (who was then the world’s richest individual, with an estimated net worth approaching $60 billion) pledged to give the Gates Foundation approximately 10 million Berkshire Hathaway Class B shares through annual contributions disbursed over multiple years. In 2006, Buffett gave Gates 500,000 of those 10 million shares — or 5% of the total — and those half-million shares had an aggregate value of approximately $1.5 billion. By the terms of Buffett’s arrangement with Gates, the former would continue to give the Foundation 5% of the remaining earmarked shares in the summer of each subsequent year (i.e., 475,000 in 2007; 451,250 in 2008; etc.). Buffett dictated this arrangement so that his yearly donations would not simply increase the Gates Foundation’s endowment, but rather would work as a matching contribution, thereby doubling the Foundation’s annual giving.