The process was quite long but it moved very quickly on their end, and my recruiter was very responsive throughout the whole process. Overall, it consisted of a phone call with a recruiter, a technical phone call with a quant, a full day onsite with 4 interviews, and finally having to send them a writing sample, a code sample, and 1-2 references.
The technical interviews were quite challenging. The first technical interview (on the phone) lasted roughly an hour and consisted of me talking about my research for the first half and then 2 technical questions during the second half (probability + applied stats). My interviewer was very friendly, seemed interested in my research, and was helpful when I got stuck on a problem. I thought I bombed it so I was shocked to get invited onsite.
The day of onsite interviews was surprisingly pleasant. I expected it to be very intimidating and cutthroat but actually all my interviewers were friendly and approachable, and seemed interested in me. The way it works is you have three interviews in the morning, and if they like you, you have another interview after lunch. All the interviews followed roughly the same format as the initial technical phone call: talk a bit about my research and then 2-4 technical questions. Some problems were coding-based, and others were more traditional probability and applied stats. After the fourth interview my recruiter let me know that I'd be moving on to the next step, which consisted of sending them a coding sample, a writing sample, and 1-2 references. My recruiter kept me posted as they heard back from my references, and shortly thereafter I got the offer.
It seems like a phenomenal place to work; much more laid back and informal than a traditional hedge fund, and has a very academic feel to it.
