If you are not a professional investor; if your goal is not to manage in such a way that you get a significantly better return than the world, then I believe in extreme diversification.
I believe that 98 or 99 percent —maybe more than 99 percent—of people who invest should extensively diversify and not trade. That leads them to an index fund with very low costs.
All they’re going to do is own a part of America. They’ve made a decision that owning a part of America is worthwhile. I don’t quarrel with that at all. That is the way they should approach it.Warren Buffett, talking to MBA students.
This video will start playing at that spot so you can hear him, and understand that the only exceptions are for professionals — and NOT ordinary investors who are relying on this money for their retirement.