Tim makes another interesting point. "Running a portfolio," he says, "is a solitary activity. For me it doesn't work to have partners. In the end, one mind in the dead of night has to make the buy and sell decisions." Teams, much less groups, are about compromises and they are bound to make less good decisions than an individual who is focused on one portfolio in which his own money is at stake. He says he can and often does make wrong decisions, but at least the decision-making process is uncontaminated.