RE:Why would anyone sellPeople sell for all kinds of personal reasons. They may have tired holding, needed money for something, wanted to reallocated, divorce, etc. When they see the news it is an opportunity to sell quantity into strength without hammering the price down. On a light trading day they are unable to unload a large number of shares without taking a deep loss on the day.
Over 3 million shares sold as of the moment. This clears out a lot of weak hands which clears the way for share price appreciation.