T. Boone Pickens, the oilman-turned-wind power advocate, has sold his 10 million Yahoo (NSDQ: YHOO) shares for a loss. Pickens said back in May that he picked up the shares simply as a bet on Carl Icahn, that the activist would be able to wrangle up some sort of deal. That didn’t happen. In an interview with the SF Chronicle, Pickens slammed Yahoo management, calling them “pathetic.” It’s not clear how much he lost, but on May 20th, when his stake was first announced, Yahoo was trading around $27. Yesterday Yahoo was just about $20, so at 10 million shares, it could be in the range of $50-$70 million (don’t worry, he’s a billionaire). And this morning Yahoo shares are down again, slipping below the $20 mark.