nazzdack stated Buffet never sells anything. In the article, it says he is selling now, and regrets selling before the meltdown in 2008. Edit - nazzdack just commented now. Stet.
This selling is incidental stuff. He seeks investments where the holding period is 'forever'. And he has acted on that philosophy to a large degree. Which means his gross and after tax are the same number. It's a big contributor to his wealth.
Maybe he finally learn his lesson, and is fearful when others are greedy (as now)? He failed to do so, in the Dow 14,000 overoptimism in 2007, and as a result his holdings went down 50%.
how poetic would it be if he blew out and went bankrupt. Going from nothing, to the richest man in the world and back to nothing again. At least he would still have his boyhood home though!