I applied through university. The process took 3 weeks. I interviewed at Fannie Mae (Washington, DC) in Mar 2015
Interview
Hour long initial interview with basic resume questions and any projects you worked on. Final round is a day's worth of 30 minute interviews that are 15 minutes of them explaining the work they do, and 15 minutes quizzing you. Lots of repetition. Most of the people were nice and interesting, only two of them actually quiz you.
Interview questions [1]
Question 1
How does Fannie Mae help the housing loan industry?