Headlands Technologies Interview ProcessTier 2

High-Frequency Trading Firm - Chicago

56 practice questions → Apply at Headlands Technologies → Learn more about Headlands Technologies ↗ Report a question from your Headlands Technologies interview

problems

10 easy 46 medium 23 hard

hires: Quant Trader, Quant Researcher, Software Engineer

Interview funnel

These stages are the quant tracks. Software engineering loops are only mapped where a stage names them.

1 Recruiter / Screen
2 Online Assessment / Coding
3 Probability & Mental Math
4 Statistics & Modeling
5 Onsite - Hardest Rounds

Recruiter / Screen

Phone - background + fit

An intro conversation about background and interest, sometimes with a quick technical warm-up.

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Editorial round — no practice problems.

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56 firmsEvery stageMust-do problems

Online Assessment / Coding

Headlands Technologies runs two kinds of first-round OA. Engineering-style candidates get a timed coding screen heavy on data-structure design and streaming or order-book problems (top-K by notional, as-of joins, max concurrent orders). Quantitative Researcher new grads report (September 2026) a single 70-minute webcam-proctored sitting in four timed blocks: - 10 statistics multiple-choice questions in 10 minutes, where an answer counts only if you tick exactly the right boxes - 4 free-response statistics problems in 24 minutes - 1 C++ problem in 20 minutes - 2 coding problems in Python, Java or C++ in 16 minutes The two statistics blocks have timed replicas below.

Quantitative Researcher (new grad)

current

2025 -> 2026

Statistics multiple choice (select all)HackerRank, webcam (reported)10 questions / 10 min (reported)

Ten statistics and machine-learning vocabulary questions in ten minutes, several of them select-all-that-apply with all-or-nothing marking: estimator bias and consistency, regression assumptions, p-values, distributions, regularisation, cross-validation and time-series basics. The replica draws a fresh mix of ten from a larger pool on every run.

Statistics interview questions (free bank)Worked solutionsPro

Free sample: 5 select-all questions in 5 minutesGenerated in the reported format, timed like the real test.Pro Full simulation: 10 questions in 10 minutes (Pro)Generated in the reported format, timed like the real test.Pro

current

2025 -> 2026

Statistics free responseHackerRank, paper allowed (reported)4 problems / 24 min (reported)

Four longer worked statistics problems with typed numeric answers: least squares from a small table, a maximum likelihood estimate, an interval or test statistic, and a conditional expectation or order statistic. About six minutes each.

Headlands statistics and modeling interviewWhat the later rounds askPro

Free sample: 2 worked problems in 13 minutesGenerated in the reported format, timed like the real test.Pro Full simulation: 4 problems in 24 minutes (Pro)Generated in the reported format, timed like the real test.Pro

Coding

current

2024 -> 2026

C++ and algorithm problemsHackerRank (reported)1 C++ problem / 20 min + 2 problems / 16 min (QR); timed coding screen (engineering)

The QR sitting ends with one problem that must be written in C++ and two more in Python, Java or C++; engineering candidates get a longer coding screen built around data-structure design and streaming problems such as top-K by notional, as-of joins and maximum concurrent orders. Warm up your C++ before the sitting.

Headlands interview questionsCandidate-reported problemsPro Coding interview questions (in-browser judge)Auto-gradedPro

Probability & Mental Math

45-60 min - video Round guide →

Probability, expectation, combinatorics, and brain-teasers with follow-ups.

Practice this round 40 problems →

#47 Two Envelopes Paradox brain-teaser medium #149 Uniform Sum Distribution With Relabeled Dice combinatorics medium #14 Optimal Stopping: Three-Roll Dice Game expectation medium #430 Hidden Face of a Painted Cube probability medium #2466 Extrapolating a Quadratic From Three Points brain-teaser medium #1391 Distinct Labelings of a Die Under Rotation combinatorics medium #674 Average Length of a Marked Fragment expectation medium #513 Simulate a 10-Sided Die from a 6-Sided Die probability medium #2365 Knights, Knaves, and Two Statements brain-teaser easy #1798 Recovering Polynomial Coefficients From Queries combinatorics medium

Statistics & Modeling

45-60 min - video Round guide →

Statistics and regression: estimator properties, p-value vs sample size, collider/selection bias, OLS pitfalls.

Practice this round 40 problems →

#1454 OLS vs. Total Least Squares: When to Minimize Perpendicular Distanceseen 2024-10 regression medium #1449 Normal-Normal Bayesian Updating with Known Variance statistics medium #1614 Low R-Squared with a Highly Significant Coefficientseen 2020-10 regression medium #2558 p-Value Equal, Sample Sizes Wildly Differentseen 2024-10 statistics medium #2066 Ridge vs. Lasso Regressionseen 2023-11 regression medium #2559 Correlation Flips Under Sample Restrictionseen 2022-11 statistics medium #2069 Ridge vs. Lasso in Cross-Sectional Factor Models regression medium #3098 OLS and Regularization Rapid Fireseen 2026-07 regression medium #2136 Equal Slopes Under Reciprocal Scaling regression easy

Onsite - Hardest Rounds

Final rounds - the toughest reported problems

The hardest reported Headlands Technologies problems across every topic. (Hard-rated only; earlier rounds cover easy/medium, so nothing repeats.)

Practice this round 40 problems →

#1315 Rolling Median in a Streaming Window coding hard #120 Optimal Stopping for Maximum of Uniforms expectation hard #522 Three-Way Duel With Rational Playersseen 2025-06 game-theory hard #310 Random Walk to the Boundary of a Square probability hard #1639 Online Covariance and Correlation (Welford-Style) statistics hard #1325 Sliding Window Median Data Structure coding hard #1499 Team Formation Game with Four Dice expectation hard #1896 AR(1) with Unknown Mean: MLE and Unit Root Testing statistics hard #1631 Minimum-Length Subarray With Sum at Least S coding hard #2048 Power and Sample Size for Sharpe Ratio Detection statistics hard #1647 Order Matching Engine Design coding hard #2553 Maximum Concurrent Orders in an Intervalseen 2025-06 coding hard

The day before

Online Assessment / Coding
Probability & Mental Math
Statistics & Modeling
Onsite - Hardest Rounds

Cheatsheet →

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Headlands Technologies round-by-round guides

Headlands Technologies interview guide: the firm, culture, roles and pay →

Stage guides for every firm: superdays · behavioral questions · market-making games

Headlands Technologies interview — FAQ

What is the Headlands Technologies interview process?

Headlands is a global HFT firm with an engineering-deep culture. Its loop is coding-and-algorithms-heavy (streaming/order-book data structures, as-of joins, top-K) plus probability, statistics, and modeling rounds. No trading game -- the bar is correct, efficient problem-solving. The loop runs 5 stages: Recruiter / Screen, Online Assessment / Coding, Probability & Mental Math, Statistics & Modeling, Onsite - Hardest Rounds.

How many rounds does Headlands Technologies have?

5 stages in total, starting with the Recruiter / Screen and ending with the Onsite - Hardest Rounds.

How do I prepare for the Headlands Technologies interview?

Work the stage notes above, then drill the Headlands Technologies interview-questions set and the Headlands Technologies online-assessment practice — each problem has a full worked solution.