Three interviews, two with managers in the group, and the third a panel interview with a case study. They called it a caselet - a short case study where I prepared 3 slides to present to them. I spent a few hours preparing slides. They company sent me a form rejection email a day after the panel caselet interview. I felt it was a little odd to get such a short rejection from a long investment of time interviewing with them. You may want to consider your time commitment before doing the same.