Citadel / Citadel Securities Interview Process & Prep
Citadel runs the largest interview funnel in the industry. QR roles emphasize ML and statistics; market-making roles (Citadel Securities) emphasize fast math, pricing, and microstructure. The funds are technically separate companies — interview structures differ slightly by business unit, but Coding + Stats are nearly universal.
The Citadel / Citadel Securities interview funnel
1. Online Assessment
90 min · HackerRank (SWE / quant-dev track)Citadel's first filter, and it cuts hard - but it is track-dependent. SWE / quant-dev track: 2-3 LeetCode-medium coding problems on HackerRank (strict time, all tests must pass, time-complexity weighted) plus a quant-finance MCQ section (probability + statistics + finance). Trading / QT track: a shorter, probability-heavy assessment. Quant Research (QR) candidates often have NO automated coding OA at all - their loop is interview-led, with live coding handled in the interviews. Per-section timing is common.
2. First-Round Phone Screen
45-60 min - videoA 45-60 min remote interview blending technical and behavioural. Core technical: one coding question (LeetCode-medium, Python or C++) plus a probability/statistics question for quant tracks. Recruiter intro up front; they screen for correct, efficient code written quickly and for genuine interest in Citadel.
3. Behavioral / Culture-Add Round
30 min · with senior researcherUnique to Citadel — they run this BEFORE the technical onsite. 'Why Citadel' + 'tell me about a project' + 1 ethics/dilemma scenario.
4. Trading / Market-Making Simulation
45–60 min · interactive · trading & QT tracksFor the trading / QT track, Citadel Securities runs live market-making simulations: you quote a two-sided market on an uncertain value, the interviewer trades against you, and you update quotes and manage inventory as the trade flow reveals information. They score quote discipline, inventory awareness, and clear reasoning under pressure far more than hitting an exact number. Rehearse the exact format with the games below.
5. Super Day - Quantitative Math
60 min · whiteboardPart of the all-day Super Day (a series of ~45-min interviews). Two or three probability/statistics problems back-to-back - expect full derivations, not just final answers.
6. Super Day - Coding
60 min · CoderPad (Python preferred)A Super Day round: one medium-hard algorithmic question plus a practical 'clean up this messy code' refactor. C++/Python emphasis; correctness, edge cases, and complexity under time pressure.
7. Super Day - ML / Statistics (QR & ML roles)
60 min · whiteboardA Super Day round for QR/ML tracks: regression, model diagnostics, regularization. They probe assumptions hard - be ready to justify 'why does this hold.'
8. Team-Fit / Final Round
45 min - with hiring teamAfter the Super Day, hiring managers across Citadel and Citadel Securities review your feedback; teams that are interested run a final fit interview. For quant/research this is often one open-ended prompt ('design an alpha' / 'a paper you would actually trade'); for SWE it is a senior-engineer team match.
Citadel / Citadel Securities interview — FAQ
What is the Citadel / Citadel Securities interview process?
Citadel runs the largest interview funnel in the industry. QR roles emphasize ML and statistics; market-making roles (Citadel Securities) emphasize fast math, pricing, and microstructure. The funds are technically separate companies — interview structures differ slightly by business unit, but Coding + Stats are nearly universal. The loop runs 8 stages: Online Assessment, First-Round Phone Screen, Behavioral / Culture-Add Round, Trading / Market-Making Simulation, Super Day - Quantitative Math, Super Day - Coding, Super Day - ML / Statistics (QR & ML roles), Team-Fit / Final Round.
How many rounds does Citadel / Citadel Securities have?
8 stages in total, starting with the Online Assessment and ending with the Team-Fit / Final Round.
How do I prepare for the Citadel / Citadel Securities interview?
Work the stage notes above, then drill the Citadel / Citadel Securities interview-questions set and the Citadel / Citadel Securities online-assessment practice — each problem has a full worked solution.