There's no use diversifying into unknown companies just for the sake of diversity. A foolish diversity is the hobgoblin of small investors. That said, it isn't safe to own just one stock, because in spite of your best efforts, the one you choose might be the victim of unforeseen circumstances. In small portfolios, I'd be comfortable owning between three and ten stocks.

All the time and effort people devote to picking the right fund, the hot hand, the great manager have, in most cases, led to no advantage.

It's human nature to keep doing something as long as it's pleasurable and you can succeed at it, which is why the world population continues to double every 40 years.

The simpler it is, the better I like it.

There is always something to worry about. Avoid weekend thinking and ignoring the latest dire predictions of the newscasters. Sell a stock because the company's fundamentals deteriorate, not because the sky is falling.

In business, competition is never as healthy as total domination.

Avoid hot stocks in hot industries.