Or he grew and matured and realized that his personal wealth wasn't all important anymore and optimizing his tail risk avoidance wasn't the most important thing going on in his life. You can change your strategy based on a change in your outlook in life and you weren't by definition "wrong" either way. Happens to most of us as we get older. Also, it's very possible that he's far craftier than we give him credit for. The U.S. economy was in a tailspin and he had billions in Berkshire Hathaway and his foundation at risk. He is hands down the most respected money manager in the world. It means a great deal when he puts down all his money on the U.S., he actually has the ability to move markets with that kind of move by changing everyone's perception of how much confidence they should have in the U.S. economy at a time when there was a high level of irrational fear. Perhaps he was just signaling that the U.S. economy had his full faith and trust in the strongest possible way, in hopes that it would become a self-fulfilling prophecy of a sort for the entire economy. At the same time, that was a relatively minor investment given the giant tail of his other investments he was swinging with it.