ProbabilityHardResearch round
Interview library
Jane Street quant interview questions
23 questions · 4 reported stages · 6 hiring locations
What does the Jane Street quant interview involve?
The Jane Street quant loop runs 4 stages: screening call, probability and mental maths, technical rounds, final / on-site. It tests probability, mental maths, market making, statistics above finance knowledge, and it is run across New York, London, Singapore, Hong Kong, Amsterdam, Austin. The questions below are ours, written to rehearse the same reasoning.
What Jane Street publishes about its hiring
Jane Street publishes interview guides by discipline. Trading interviews start by phone and finish in person, and the firm says it does not test finance or economics knowledge. Checked against the firm's own pages on 18 October 2026.
Verified: stated by the firm
- Every application is reviewed by a person, and Jane Street aims to respond to every applicant, ideally within about a week. [Jane Street, Trading Interviews]
- Applicants are considered for every open role, not only the one they apply for. [Jane Street, Interviewing]
- Trading interviews start with phone interviews and end with an in-person final round. [Jane Street, Trading Interviews]
- The trading final round may include problem solving, probability and statistics, coding in any language, data analysis and general interests, all asked by quantitative traders. [Jane Street, Trading Interviews]
- Quantitative trading interviews do not test finance or economics knowledge. [Jane Street, Interviewing]
- Quantitative research interviews mix the trading and software engineering processes. [Jane Street, Interviewing]
- Software engineering candidates take a technical interview over Zoom, then in-person final rounds focused on collaborative coding problems. [Jane Street, Preparing for a Software Engineering Interview]
Official process: Quantitative trading
- Application reviewed by a person
- Phone interviews
- In-person final round
Estimate: our modelling and compilation
- The 4-stage loop below is compiled from public sources and candidate reports, not published by Jane Street as a single sequence.
- Modelled mid-level total compensation, Quant Researcher: about $575k USD. A KnowQuant estimate, not an employer figure.
- Modelled mid-level total compensation, Quant Trader: about $600k USD. A KnowQuant estimate, not an employer figure.
- Modelled mid-level total compensation, Quant Developer: about $450k USD. A KnowQuant estimate, not an employer figure.
- The 23 practice questions are written by KnowQuant to rehearse the reasoning; they are not Jane Street's questions.
Not stated by the firm
- - Exact number of phone rounds
- - Pay ranges outside jurisdictions that require them
Jane Street 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.
- Interviewing
Jane Street · read 18 Oct 2026
- Trading Interviews
Jane Street · read 18 Oct 2026
- Preparing for a Software Engineering Interview
Jane Street · read 18 Oct 2026
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.
- Stage 1Screening call
What happens in the screening call at Jane Street?
Recruiter conversation and background discussion. It is stage 1 of 4 in the Jane Street loop, and candidates who clear it move to the probability and mental maths.
Next step: Probability and mental maths - Stage 2Probability and mental maths
What happens in the probability and mental maths at Jane Street?
Fast-paced expected-value and market-making games. It is stage 2 of 4 in the Jane Street loop, and candidates who clear it move to the technical rounds.
Next step: Technical rounds - Stage 3Technical rounds
What happens in the technical rounds at Jane Street?
Algorithms, problem solving, and for engineers a strong functional-programming component. It is stage 3 of 4 in the Jane Street loop, and candidates who clear it move to the final / on-site.
Next step: Final / on-site - Stage 4Final / on-site
What happens in the final / on-site at Jane Street?
Multiple interviewers, trading games, and estimation under time pressure. It is stage 4 of 4 in the Jane Street loop and it is the final decision point.
Next step: rehearse the practice set
Practice questions matched to this loop
Filtered to the topics Jane Street draws on for the roles it hires: probability, mental maths, market making, statistics, brainteaser, machine learning, algorithms, c++ and systems. Written originally for this platform, so they rehearse the reasoning rather than republish anyone's question bank.
Market makingHardTrading round
You are quoting a market and get lifted five times in a row on the offer, in full size, by the same counterparty. Nothing else in the market has moved. What do you do?
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?
Mental mathsStandardFirst round
Estimate the square root of 4,600 to one decimal place in under ten seconds.
Mental mathsStandardTrading round
A contract pays 100 if an event happens and 0 otherwise. It trades at 37. You think the true probability is 41%. You can trade 500 contracts. What is your expected edge?
Market makingStandardTrading round
I roll two fair six-sided dice and pay you the product. Make me a market, two wide.
Market makingStandardTrading round
Make a market on the number of petrol stations in the United Kingdom.
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?
Mental mathsWarm-upPhone screen
What is 17 × 23, without writing anything down?
Jane Street 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 Jane Street
How many interview stages does Jane Street run?
4 published stages: screening call, probability and mental maths, technical rounds, final / on-site. The sequence is the same across every office we track.
What topics does the Jane Street quant interview test?
Mainly probability, mental maths, market making, statistics. Jane Street hires for 3 quant families, so the technical rounds are weighted to the role rather than to finance knowledge.
How hard is the Jane Street quant interview?
Hard by market standards. Our practice set for this loop runs to 23 questions, sorted with the hardest first, and the backgrounds that clear the bar are typically olympiad mathematics and competitive programming.
What does Jane Street pay after a passed loop?
Jane Street benchmarks at roughly 125% 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 Jane Street hire quants?
New York, London, Singapore, Hong Kong, Amsterdam, Austin. Each market carries its own benchmark in the local currency.
Are these real Jane Street 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 Jane Street 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
- -Olympiad mathematics
- -Competitive programming
- -Physics and mathematics undergraduates
- -Poker and games backgrounds
Live opportunities
Preparing for Jane Street? See roles like theirs
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.
Interview intelligence
Prepare for Jane Street against the whole market
The loop, the reasoning it tests, and what the role pays once you clear it.