I applied through an employee referral. The process took 4 weeks. I interviewed at Citadel Securities in Dec 2022
Interview
One technical interview and one behavior interview. Tech interview wasn't that hard. The interviewer was nice and helpful. The behavior interview last a bit long and was very specific. Overall I would say it was fair but I still failed.
I applied online. I interviewed at Citadel Securities (Sydney) in Jun 2026
Interview
The process includes 4 technical interview and 1 final behavior interview, the primary language is Python. You will scheduled for next round if passed previous round, I failed on 2nd round
Interview questions [1]
Question 1
1st round: questions about tcp/udp, heap, queue, thread/process + coding exercise about parse file
2nd round: ask about project experience, implement decorator
I applied online. I interviewed at Citadel Securities (Chicago, IL) in Feb 2026
Interview
First round is behavioral and technical and second round is superday. Then is final round and team matching. Superday was virtual and 45 min each, all same format, with beginning behavioral questions, a huge chunk on system design, and final questions at the end.
Interview questions [1]
Question 1
System design, create a stock options book using dict
Went through 4 rounds of technical interview + 1 round of leadership round.
This was for a C++ internship role. Process and questions were very dependant on your interviewer, but it is definitely C++ heavy and should be familiar with low level stuff