Billionaire investor Warren Buffett announced plans Sunday to give the bulk of his roughly $42 billion fortune to five foundations in annual gifts of stock starting next month. Moreover, his vast holdings of Berkshire Hathaway Inc. stock had been expected to go largely to the Susan Thompson Buffett Foundation, begun by his late wife. Her foundation has given millions of dollars to hospitals, universities and teachers, as well as to Planned Parenthood and other abortion rights groups. Instead the 75-year-old chairman and chief executive of Berkshire Hathaway plans to give the largest contribution to the Bill and Melinda Gates Foundation, established by Buffett's friend and Berkshire board member Bill Gates. Buffett's gift will increase the resources of the Gates Foundation, which is already the world's largest philanthropy with assets of about $29.1 billion.