Warren E. Buffett announced plans to step down as CEO of Berkshire Hathaway Inc. (BRK.A, BRK.B) at the end of the year, with Greg Abel set to take the helm as the conglomerate's next leader, according to a letter released Nov 10. "I would like to keep a significant amount of 'A' shares until Berkshire shareholders develop the comfort with Greg that Charlie and I long enjoyed,†Buffett wrote, referring to the late Charlie Munger. He added that "the acceleration of my lifetime gifts to my children's foundation ...