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Hudson River Trading quant interview questions

17 questions · 3 reported stages · 5 hiring locations

What does the Hudson River Trading quant interview involve?

The Hudson River Trading quant loop runs 3 stages: online assessment, technical phone screens, on-site. It tests probability, statistics, machine learning, brainteaser above finance knowledge, and it is run across New York, London, Chicago, Singapore, San Francisco. The questions below are ours, written to rehearse the same reasoning.

What Hudson River Trading publishes about its hiring

Hudson River Trading has described its campus software engineering process on its own blog: a timed take-home, roughly two phone interviews and a full day of interviews. It says the process keeps changing. Checked against the firm's own pages on 18 October 2026.

Verified: stated by the firm

Official process: Campus software engineering (2021 to 2022 description)

  1. Timed take-home test
  2. Roughly two phone interviews
  3. Full day of back-to-back interviews

Estimate: our modelling and compilation

  • The 3-stage loop below is compiled from public sources and candidate reports, not published by Hudson River Trading as a single sequence.
  • Modelled mid-level total compensation, Quant Researcher: about $550k USD. A KnowQuant estimate, not an employer figure.
  • Modelled mid-level total compensation, Quant Developer: about $460k USD. A KnowQuant estimate, not an employer figure.
  • Modelled mid-level total compensation, HFT / Low-Latency Engineer: about $500k USD. A KnowQuant estimate, not an employer figure.
  • The 17 practice questions are written by KnowQuant to rehearse the reasoning; they are not Hudson River Trading's questions.

Not stated by the firm

  • - A current published stage list for algorithm development (quant research) roles
  • - Pay ranges outside jurisdictions that require them

Hudson River Trading sources

Primary material read while writing this piece. Firm specific practices are attributed to the firm that published them and should not be read as industry wide.

The loop as candidates report it (compiled, not official)

Each round answers the question candidates actually ask, then points at the round that follows it.

  1. Stage 1Online assessment

    What happens in the online assessment at Hudson River Trading?

    Algorithmic problems under time limit. It is stage 1 of 3 in the Hudson River Trading loop, and candidates who clear it move to the technical phone screens.

    Next step: Technical phone screens
  2. Stage 2Technical phone screens

    What happens in the technical phone screens at Hudson River Trading?

    Two rounds of algorithms and systems reasoning. It is stage 2 of 3 in the Hudson River Trading loop, and candidates who clear it move to the on-site.

    Next step: On-site
  3. Stage 3On-site

    What happens in the on-site at Hudson River Trading?

    Deep C++ or Python, systems design, and a research or statistics component. It is stage 3 of 3 in the Hudson River Trading loop and it is the final decision point.

    Next step: rehearse the practice set

Practice questions matched to this loop

Filtered to the topics Hudson River Trading draws on for the roles it hires: probability, statistics, machine learning, brainteaser, algorithms, c++ and systems. Written originally for this platform, so they rehearse the reasoning rather than republish anyone's question bank.

ProbabilityHardResearch round

You draw cards one at a time without replacement from a standard 52-card deck until the first ace appears. What is the expected number of cards drawn?

StatisticsHardResearch round

Your alpha shows a strong in-sample relationship with next-day returns, but the effect halves out of sample. Give three explanations that are not overfitting.

AlgorithmsHardEngineering round

You receive a stream of order-book updates and must report the maximum trade price in the last N events at every step. How?

C++ and systemsHardEngineering round

Your median tick-to-trade latency is fine but the 99.9th percentile is ten times worse. Name the likely causes.

Machine learningHardResearch round

A gradient-boosted model predicts next-hour returns with an out-of-sample R² of 0.004. Is that useful?

BrainteaserHardFirst round

One hundred prisoners each open 50 of 100 boxes searching for their own number; all must succeed or all fail. What strategy beats a vanishingly small success rate?

ProbabilityStandardFirst round

Two people independently pick a real number uniformly from [0, 1]. What is the probability the two numbers differ by more than 0.25?

ProbabilityStandardFirst round

A random walk starts at 0 and moves +1 or −1 with equal probability each step. What is the probability it reaches +3 before it reaches −5?

StatisticsStandardResearch round

You backtest 200 signals and the best one has a Sharpe ratio of 2.4. Should you trade it?

StatisticsStandardFirst round

Two return series each have a correlation of 0.6 with a third. What is the tightest bound you can put on their correlation with each other?

AlgorithmsStandardEngineering round

Design a data structure that supports insert, delete and get-random-element, all in expected O(1).

AlgorithmsStandardEngineering round

How would you implement a limit order book supporting add, cancel and match, and what is the complexity of each?

C++ and systemsStandardEngineering round

Why might std::unordered_map be a poor choice on a latency-critical hot path?

C++ and systemsStandardEngineering round

Explain false sharing and how you would detect it in a multi-threaded market data handler.

Machine learningStandardResearch round

Why is k-fold cross-validation usually wrong for financial time series, and what do you use instead?

BrainteaserStandardFirst round

You have 25 horses and a track that races five at a time, with no timer. What is the minimum number of races to find the fastest three?

ProbabilityWarm-upPhone screen

You flip a fair coin three times. Given that at least one flip came up heads, what is the probability all three were heads?

Hudson River Trading interview questions by city

The same loop, read against the local market: what the desk hires for, how the round is run there, and what a passed loop pays in the local currency.

Questions candidates ask about Hudson River Trading

How many interview stages does Hudson River Trading run?

3 published stages: online assessment, technical phone screens, on-site. The sequence is the same across every office we track.

What topics does the Hudson River Trading quant interview test?

Mainly probability, statistics, machine learning, brainteaser. Hudson River Trading hires for 3 quant families, so the technical rounds are weighted to the role rather than to finance knowledge.

How hard is the Hudson River Trading quant interview?

Hard by market standards. Our practice set for this loop runs to 17 questions, sorted with the hardest first, and the backgrounds that clear the bar are typically competitive programming and computer science graduates.

What does Hudson River Trading pay after a passed loop?

Hudson River Trading benchmarks at roughly 122% of the market figure for the same role and seniority. Published ranges are held per role, seniority and market in the local currency.

Where does Hudson River Trading hire quants?

New York, London, Chicago, Singapore, San Francisco. Each market carries its own benchmark in the local currency.

Are these real Hudson River Trading interview questions?

No. Stage detail is compiled from public sources and candidate reports and labelled as such. Every question is written originally for this platform to rehearse the same reasoning, so nothing here republishes a firm's own question bank.

How Hudson River Trading compares

Side by side on modelled pay, interview stages, offices and the roles each firm hires for.

Roles this loop leads to

Each one carries a published benchmark by seniority and market.

Backgrounds that clear this bar

  • -Competitive programming
  • -Computer science graduates
  • -Systems engineering
Hudson River Trading firm profileEvery firm's loop

Live opportunities

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Open vacancies we track at quant firms, grouped by role and city. Adverts are anonymised.

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Stage detail is compiled from public sources and candidate reports and is labelled as such. Questions are written originally for this platform. We do not republish any firm's proprietary interview questions.

Methodology

Figures are expressed as annual total compensation (base salary plus expected performance bonus) in the reference market's local currency, converted from a US dollar base. They describe typical market ranges rather than any individual offer, and exclude sign-on payments, deferred equity and carried interest. Portfolio-manager figures reflect formulaic profit-share arrangements and are therefore far more dispersed than any other role.

KnowQuantIndex 2026.1 · Updated September 2026

Modelled bands describe the market, not an individual offer. Where an employer states pay, the stated figure is used and labelled as such.

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Prepare for Hudson River Trading against the whole market

The loop, the reasoning it tests, and what the role pays once you clear it.