I applied through my university career services. The first round consisted of two 1:1 interviews with a Senior Associate Consultant and a Managing Director. Both started with the typical behavior questions which was then followed by a market sizing question. The questions were not too difficult, however, they did question my assumptions to pressure me a bit in defending my answer. The second (and final) round was at their Greenwich office, an hour from Manhattan. I had three back-to-back interviews for a total of 3 hours. They were all with very senior executive people (VPs, Sr. VPs). Again, each asked me a couple of fit questions but the interview was mainly focused on the market sizing questions. and brainteasers. The questions were definitely unusual, and I thought, pretty challenging. Overall, you need to be very quantitative to enjoy and have success in their interviews. Most of the employees have some sort of engineering or mathematics background.