If you are a professional and have confidence, then I would advocate lots of concentration. For everyone else, if it’s not your game, participate in total diversification. If it’s your game, diversification doesn’t make sense. It’s crazy to put money in your twentieth choice rather than your first choice. . . . [Berkshire Vice-Chairman] Charlie

In short, all of us in the industry made a fundamental underwriting mistake by focusing on experience, rather than exposure.”