For the third time since the start of our composite ranking in 2010, the University of Pennsylvania's Wharton School has claimed top honors for having the best MBA program in the U.S. Of all the schools, Harvard Business School still leads the pack overall, having ranked first seven out of a dozen times. Stanford Graduate School of Business has been No. 1 four times. The school with the most momentum? Yale School of Management which went from a rank of 17 in 2013 to eighth best this year.