Reliance Insurance and Home Insurance were run into the ground, for example, their promises proved to be worthless. - Warren Buffett

As practiced, diversification makes very little sense for anyone that knows what they’re doing. Diversification is a protection against ignorance. If you want to make sure nothing bad happens to you relative to the market, sure you should diversify. There's nothing necessarily wrong with that...but in our view, true diversification is simply a confession that you do not truly understand the businesses that you own. If you find just 3 wonderful businesses in your lifetime, you'll get very rich.

this holding has proved extraordinarily profitable thanks to a move by your Chairman that combined luck and skill — 110% luck, the balance skill.

In addition to being independent, directors should have business savvy, a shareholder orientation and a genuine interest in the company. The rarest of these qualities is business savvy — and if it is lacking, the other two are of little help. Many people who are smart, articulate and admired have no real understanding of business. That’s no sin; they may shine elsewhere. But they don’t belong on corporate boards.