I interviewed at Citadel Securities (New York, NY)
Interview
Hard, They asked expected value and confidence interval questions. Definitely should be familiar with coin questions, dice roll questions, etc. Behavioral questions were just a run through resume and asking about previous internships.
Interview questions [1]
Question 1
1. coin A flips heads 2/3 times, coin B flips heads 1/3 time. Prob of it being coin A if 3 flips in a row it was heads?
I interviewed at Citadel Securities (New York, NY)
Interview
Online Assessment followed by 2 rounds of interviews with traders who ask you general probability questions / market making games. Then an onsite in the office which had a mix of a group game and 3 rounds of interviews; which had a mix of statistics and probability. Game was also similar in concepts. Very traditional quant process.
I applied online. The process took 4 weeks. I interviewed at Citadel Securities (Sydney) in Mar 2026
Interview
5 rounds - oa, 4 virtual interview rounds. oa consisted of probability, expected value and statistics questions. 1st round consisted of easy problems and market making. 2nd round had hard probability questions.
I interviewed at Citadel Securities (London, England)
Interview
Questions in earlier rounds were fairly easy. Final round was more difficult and open ended but overall quite interesting. One of the interviewers was very rude and kept going on his phone.