Because it's profitable for them at present. Shorties, you've made your money. You're still making money with the dips. Hoping this recent dip goes lower to make even more? Clean up boys. Because the Markman - Claims Construction ruling is coming out soon on the Patent Infringement and then the trial starts. You need to clear out and move on before that happens or have your profits squeezed out of you. Don't linger too longs shorties. You'll wish you hadn't.