Berkshire Hathaway’s CEO Warren E. Buffett announced the resignation of David L. Sokol, Chairman of several Berkshire subsidiaries, according to a Bloomberg report.Buffett said that late in the day on March 28 he received a surprising letter from Dave, delivered by his assistant. Sokol said in the letter, "As I have mentioned to you in the past, it is my goal to utilize the time remaining in my career to invest my family's resources in such a way as to create enduring equity value and hopefully an enterprise which will provide opportunity for my descendents and funding for my philanthropic interests. I have no more detailed plan than this because my obligations from Berkshire Hathaway have been my first and only business priority."Effective with Sokol's resignation, the current President and CEO of MidAmerican Holding Company, Greg Abel, will become its Chairman; Todd Raba, President and CEO of Johns Manville, will become its Chairman; and Jordan Hansell, President of NetJets, will become its Chairman and CEO.