Jane Street
4.2 of 5 17 reviews
www.janestreet.com New York, NY 150 to 499 Employees

Jane Street Interview Questions & Reviews

Updated Jul 1, 2014
All Interviews Received Offers

Getting the Interview 

55%
35%
8%

Interview Experience 

55%
31%
12%

Interview Difficulty 

Average Difficulty
418 candidate interviews
Relevance Date Difficulty
in

No Offer

Positive Experience

Difficult Interview

Trading Intern Interview

Trading Intern

I applied online and the process took 3 weeks - interviewed at Jane Street in February 2014.

Interview Details – Applied online. Contacted for interview the day after. Made it to round 2. Interview was quite difficult. Make sure to review probability and statistics for the interview. Don't bother studying behavioral questions. Most annoying thing was how Jane Street stopped replying after round 2, so I assume I didn't make past round 2.

Interview Question – The interviewer gives you 100 blank cards, and you can write a single positive integer on each card. The interviewer looks at the cards when you're done (so he knows the probability distribution of the deck), then shuffles the deck. The interviewer guesses the top card of the deck, and if he's right, he makes in $ the number written on the card. What numbers should you write on the cards to minimize the expected return of the interviewer?   View Answers (2)

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Quantitative Trader Interview

Quantitative Trader

I applied online and interviewed at Jane Street.

Interview Details – 30 minute phone interview. The interviewer asked approx. 9 math questions ( 3 mental math, 3 probability and 3 word problems). I was given approx. 30 seconds per question. Answered at least 7 of them correctly.

Interview Question – What is the probability of getting a sum of 10 if you roll three dice?   View Answer

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Average Interview

Quantitative Trader Interview

Quantitative Trader

I applied through college or university - interviewed at Jane Street in November 2013.

Interview Details – Had 2 rounds of phone interview. The first round had about 5 questions, 2 on basic arithmetic, 2 on probabilities (standard card problems), and 1 brainteaser. The interviewer, though late for the call, gave a lot of guidance. The 2nd round interviewer was really rude. He was giggling the whole time and hung up abruptly when I got the first probability question wrong.

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

We want your feedback – Is this interview information helpful to you?  Yes | No

No Offer

Neutral Experience

Average Interview

Software Development Intern Interview

Software Development Intern

I applied through college or university and the process took 3 weeks - interviewed at Jane Street in January 2014.

Interview Details – After submitting an application on my University website, I was contacted a few weeks later to set up a coding interview by phone. The interview focused on linked list implementation, optimization and optimal algorithms for searching, inserting, etc. All employees I interacted with in the process were very kind and knowledgable, seems like a great company!

Interview Question – Optimizing search for smallest (inner) list within in a list of lists   Answer Question

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Difficult Interview

Assistant Trader Interview

Assistant Trader

I applied online and the process took 2 weeks - interviewed at Jane Street.

Interview Details – telephone interviews just brain teasers. Missed a trick on the first interview but they still wanted to schedule a second one so it's mostly about the reasoning.

Interview Question – person A has a 30 sided and person B has a 20 sided die. both players role and the person with the highest role win (on a draw B wins). the loser pays the winner the value of the winners die.
1. calculate expected value of this game for player A (easy)
2. how does this value change if player B can re-roll and when should he re-roll.
3. now how much is it worth for player A to get a re-roll option in this scenario.
4. remove player A reroll. how many re-rolls do player B need in order for him to be a favorite in the game.

i believed i solved 4 and 2 I had a decent idea but 3 is very difficult since optimal strategy might change based on opposing players optimal strategy.
  View Answers (5)

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Difficult Interview

Trader Intern Interview

Trader Intern

I applied online and the process took 4+ weeks - interviewed at Jane Street in March 2014.

Interview Details – applied online got an interview the next day. passed the first round waiting for the second round. The interviewer is nice. She did not ask a lot about my background. Lots of mental math and probability questions. The questions are not that tough. no pencils and paper for the first round.

Interview Question – Basketball player A and B. Game 1 and 2. In both game, A has a higher shooting average than B. Is it possible that B has a higher overall shooting average. Give an example if possible.   View Answers (5)

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Intern Interview

Intern

Interviewed at Jane Street

Interview Details – Applied online and heard back within about a week. Good communication; had to demonstrate excellent knowledge of excel and mathematical skills. I did not receive an offer in the end but would be happy to apply again. Have heard great things.

Interview Question – Had to do complex coding on excel   Answer Question

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Positive Experience

Difficult Interview

Software Development Engineer Intern Interview

Software Development Engineer Intern

The process took 3 days - interviewed at Jane Street in March 2014.

Interview Details – The interview process began with a conversation and resume drop at a career fair, but I was told that applying online would have been the same. A couple weeks later, I received and email asking for availabilities in a two-week window.

The first interview lasted about 1 hour 15 minutes. Interviewer was very friendly, and passionate about his work. It was a phone interview with live coding on code.stypi.com. Questions were straightforward. After a quick intro we went straight into the first question topic, power sets. After question, given an alternate solution involving binary strings. Remaining 30 minutes or so devoted to Q+A. Heard back in 15 minutes (next round)

Second interview was also a little over 1 hour. Most of the time devoted to a single coding question (it was up to me to break it into parts). Key idea was to break an abstract idea into codable elements, show your thinking process, and make a useable interface. Heard back the following week, no offer.

Both interviewers were every friendly and did a good job at maintaining a moderate-to-high level of difficulty (occasionally commenting "are you sure?", "um", or "okay" to hint at whether or not I was going in the right direction). First interview was moderate, second quite difficult. Both questions were interesting and unique as far as I could tell.

Interview Questions

  • Write a function to make a power set (as a list of lists) from a set (as a list). Wrote code in ocaml, although I was told that any language would do.   View Answer
  • Given a 0-9 numerical keypad and three chess pieces (pawn, knight, queen), use any language to write a function such that Input(piece, location)->Output(# of possible phone numbers). Code must compile and run.   View Answer

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Trader Interview

Trader

Interviewed at Jane Street

Interview Details – Pre-Interview(10min), Interview(30min)

Interview Question – How many tons does the ocean weigh?   Answer Question

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response

No Offer

Neutral Experience

Assistant Trader Interview

Assistant Trader

Interviewed at Jane Street

Interview Details – They were pretty slow in their follow up after interviews, I had to email them every time before they'd remember to send me to the next round. The interviews were interesting and technical. Be prepared to answer questions quickly, without pen and paper, in the first round at least. Later on the questions get harder but they allow you to use writing materials.

Interview Question – I did initially misunderstand this question and had to be helped along, but it is fairly difficult to do on the fly anyway: "We're playing a game with an unbiased 30-sided die. Before we roll, we both pick (distinct) numbers between 1 and 30, and then we roll the die. If the number that appears is closer to the number I picked, you pay me, in dollars, the number on the die; if it is closer to the number you picked, I pay you, in dollars, the number on the die; if it is equidistant we do nothing. What's the optimal strategy - do you go first or second, and how do you pick your number? What's your expectation?"   View Answers (2)

Was this interview helpful?  
Yes | No
Flag Interview  |  Add Employer Response
RSS Feed Embed
Interviews for Top Jobs at Jane Street

See What Jane Street Employees Are Saying

1 person found this helpful

 Former Trader

Pros: “The payout is very very satisfying. It is very challenging. You are working in an environment with a lot of very very smart people.” Full Review


Worked for Jane Street? Contribute to the Community!

The difficulty rating is the average interview difficulty rating across all interview candidates.

The interview experience is the percentage of all interview candidates that said their interview experience was positive, neutral, or negative.

Your response will be removed from the review – this cannot be undone.

Glassdoor is your free inside look at Jane Street interview questions and advice. All 418 interview reviews posted anonymously by Jane Street employees and interview candidates.