Fascinating, counter-intuitive bit from HBS Professor Noam Wasserman:

In my data, by the time start-ups raise the third round of financing, 52 percent of founder C.E.O.’s have been replaced. In three-quarters of these situations, the board fired the founder. In the remaining cases – by far the minority – the founder raised his hand and said, “There’s got to be someone better than me to lead us to the next stage.” And I found that the most successful of founders, the ones who led their start-ups to completing key milestones the quickest, were actually the first ones to get fired.