Phone Screen with a few behavoiral questions, 1 45 minute 1st round interview with a behavorial section and a case interview, and a final round consisting of 2 back-to-back 45-minute interviews, which are only case interviews with one interview being one case and another interview being two cases. Behavioral interviews will ask about your understanding of the Fannie Mae business as well as questions about past work experience and experience working with data. Each case interview gets progressively harder, and a calculator is allowed. Lots of financial graph interpretation and computations, as well as how you would collect data and analyze it. Process moves pretty quick and took about 3 weeks, they update you pretty quickly and after each interview i got a decision/moving forward notification within 2-3 business days. If you get rejected after the final round the recruiter calls you before they send the genric email rejection which I have not seen in any of my oher interviews. You are interviewed primarily by Senior or Lead Data Science Associates which are people who have been with the company for around 5 years. I would say the interview process is very fair but you can't really prepare for the cases that much as they arent mangement consulting style cases so just be ready to think on your feet and walk your interviewer through your reasoning. The actual computations on the case were pretty easy so I would not worry much about the math (mostly algebra)