It's happened before (and with many other companies, not just Apple). It was trading higher over the last week in the lead up to the event, then the reality kicks in and people realize "Oh, there's really nothing groundbreaking that's going to triple the value of the company? Sell sell sell!" It's still up 11% (at this moment) from 90 days ago, and down about 0.5% from 5 days ago.