SErena Williams has been haunted for several years by the question of when she would end her tennis career, much like Roger Federer, who is almost the same age. The answer has long remained open, but Williams has made it increasingly clear in recent times that she is working on a career off the tennis court. The strongest signal came in March when she announced a corporate milestone. She said the venture capital firm she founded, Serena Ventures, had raised money from outside investors on a large scale for the first time, totaling $111 million.
