The Bill & Melina Gates Foundation (B&MGF) is the largest transparently operatedcharitable foundation in the world, founded by Bill and Melinda Gates in 2000 and doubled in size by Warren Buffett in 2006. The primary aims of the foundation are, globally, to enhance healthcare and reduce extreme poverty, and, in the United States, to expand educational opportunities and access to information technology. The foundation, based in Seattle, Washington, is controlled by its three trustees: Bill Gates, Melinda Gates, and Warren Buffett. Other principal officers include Co-Chair William H. Gates, Sr. and Chief Executive Officer Patty Stonesifer. It has an endowment of US$38.7 billion as of December 31, 2007.