Famous author and Professor Roger Ibbotson says investors need to diversify their portfolio because it essentially helps in reducing risk.”In any race, there’s going to be a winner but that doesn’t mean you should abandon all the other kinds of investments because the winner of this race isn’t going to be the winner of the next race, and if you knew which one to take, of course, that would be great, but we don’t really know which part of the market is going to do best in the future, and that’s why you diversify, essentially, because what it does in the end is, it reduces your risk,” he says.