10/3/09

Hey Guys,

I have my first round phone finance interview with JSC in 4 days. What should I be expecting? Anyone who had their ph interview with JSC.. your insight would be of great help.

Also, any site where I can get a good prep?

Comments (97)

10/3/09

they will pretty much just fuck you and then not call you for 2nd rounds

Financial Modeling

10/3/09

unless ur a god. prepare to die.

10/4/09

.

10/3/09

to the op: there are lots of posts with jane street's questions if you search on this side

...i have a in person first round with them in a few days. having read the posts on this site about them (this thread doesnt help either).. i'm prepping for getting butchered :|

10/3/09

to op: How long did it take you to hear back from JSC after submitting your application?

10/3/09

I've heard JSC is more in the market making business than other top prop shops, is this correct?

10/3/09

Does anyone know if they invite you in for an in-person interview if you are located out of state ?

Thanks.

10/11/09

got the interview.
have to agree with the first two posters--
you're f***ed.

10/11/09

I interviewed with JSC. The first round questions were honestly pretty easy if you're not terrible at math. I was asked to do some mental computations, and a basic probability question regarding dice.

Second round questions were a bit harder, but still reasonable. They are all mental problems (i.e. no pencil, no paper).

Third round--harder still. One of the questions I got was: my roommate and I are having a house party. We invite 15 couples. At the party, everyone must shake hands with everyone whom they do not already know. At the end of the party, I can't remember the number of people I have met, so I go ask all other people at the party how many hands they have shaken, and they each tell me a different number. You do not shake hands with yourself or your 'partner' (the person with whom you came). How many hands did my roommate shake?

Fourth round--same as third, but they have you bet on the answers you give. In all rounds, they ask how sure you are about your answers (as a percentage). In this round, if you are asked to give a 95% confidence interval, and then a 90% confidence interval, you should understand how to construct one. They'll ask you to 'make a market' on your answer, and ask how much you're willing to risk per point. So if the answer to the question which you're not (unless you're Rain Man) going to be able to compute in your head is, say, 22.375148 and you go 20-30, they're going to ask you to narrow it. They're going to make you do this quickly, by the way. They might say they want a two point market. Then you go 24-26, and you're given at 24. Then you go, say, 20-22, and you're lifted at 22. They then ask for a 1 point market, and you go 22.5-23.5, and given at 22.5. At which point, they're likely to ask you how much money you have lost making the market. You need to be able to do this stuff in your head. If you can't, well, you wouldn't have made it to the 4th round in any case.

5th round was an in-office interview. It's the only time that you're asked ANY fit questions. It's also the only time I went to their offices (as I was in London, and they VAST majority of their traders sit in NYC). Nice offices. Anyway, a few more brainteasers. At this point, you have to be pretty strong at math, so the questions I got were actually easier than the 4th round questions. One of the questions I got was: I'm thinking of a 10-digit number, where each digit represents the number of that ordinal number in the whole number. So, the first digit represents the number of 0's in the whole 10 digits. The second digit represents the number of 1's in the whole 10 digits. And so on. The first digit is not a '0.' What is my number. Once again, there was no pencil and no paper. And you're given about 20-30 seconds to respond.

There were a couple of game theory questions in the earlier rounds, but I don't know if everyone gets the same sorts of questions, as I have a mathematics degree, was a math olympian, and have a graduate degree in economics (so if I couldn't do remedial game theory, I was in trouble).

I didn't end up getting the job. Apparently, I messed up in one of my last interviews. I have a good deal of respect for the mathematical aptitude of the people there, though, and if you're good at math (not the shit from a classroom--I mean if you're naturally good), you will probably fit right in. They don't care about anything else until the final round, so good luck.

12/8/09

brotherbear, did you get feedback from JSC on what was it that you "messed up" in your round 5 interview?

12/8/09

That was the worst part.

12/9/09

yeah, these guys are never forthcoming with feedback. i've heard the same from people who've interviewed with other shops (drw/sig and the lot). i guess they don't want the "what we're looking for" to become public...

in any case, if it's any consolation, good job getting that far in the process. sounds like a tough nut to crack.

10/11/09

OK so I don't mean to be rude - but is it the norm that someone with a 3.4 in econ can be pulled for interviews at a HF as top-tier as Jane Street? And that too as quant as Jane Street? I realize GPA means little to nothing as far as long term success or capabiity - I mean, Sandy Weill nearly failed out of college, right? - but for better or worse, it is the dominant screening mechanism for getting a job. I'm guesssing that the OP is from a target, but even then, are these stats that would need to be supplanted by something else quite potent.....say networking?

10/11/09

Are all prop trading interview questions as hard as this, or is JSC an anomaly?

Also, how would you go about learning how to answer the market-making question? Does that kind of stuff appear in econ/finance classes or in books?

Thanks in advance.

10/11/09

I'm assuming you meant 6210001000. Anyway, you wouldn't learn how to do a problem like this in any class. A good brainteaser shouldn't be a test of knowledge, but of ability. They're meant to test your way of thinking, not what you already know.

Whilst I used to think they were an absolute waste of time when I was monkey, having sat on the other side of the table, you'd be surprised how few kids can actually answer these. And, because brainteasers don't serve their purpose if the candidate has already heard the question, places like Jane Street ask A LOT of brainteasers. It's a way to make sure that over-zealous DBs with interview performance anxiety get discovered before getting a job offer. These firms are looking for alpha. If you can't think creatively (which isn't something that is obvious from reading a CV), how are you going to add to a firm's trading operations?

I'm not saying that being good at brainteasers is the only thing that is important in being a good trader, but it's a signal. Just like going to a good school is a signal. Just like having a strong GPA is a signal. Just like having good contacts is a signal (especially for sales or M&A, but knowing people in the market is important for traders too). The truth is--not everyone who comes out of an Ivy, Oxbridge or LSE with good grades is going to be cut out to be a trader. And there are very few junior trader positions available every year for all of the applicants applying for the positions, most of whom have (basically) the same resume.

So, they're an equalizer. I went to a debate the other day where Professor Bhagwati from Columbia said (in a remark completely unrelated to the topic-at-hand) that after teaching at MIT and Columbia, there were always 20-30% of the class that had no business attending those schools. And due to grade inflation, loads of kids graduate with a 3.5 from a good schoool, so we have to find a way of discovering if you're part of that 20-30%.

10/12/09

Third round--harder still. One of the questions I got was: my roommate and I are having a house party. We invite 15 couples. At the party, everyone must shake hands with everyone whom they do not already know. At the end of the party, I can't remember the number of people I have met, so I go ask all other people at the party how many hands they have shaken, and they each tell me a different number. You do not shake hands with yourself or your 'partner' (the person with whom you came). How many hands did my roommate shake?

This question is answerable if you draw the different people in a circle and start pairing the up two different roommates based on the number of hands they shake. The person who shakes 30 hands will be the roommate of the person who shakes zero hands. The person who shakes 29 hands will be the roommate of the person who shook only one hand. So on and so forth. The original roommate will have shaken 15 hands. Right?

10/13/09

.

10/12/09

no worries its all good :)

12/8/09

Had my 3rd round a week ago. Found out today that I didn't get a 4th and was pretty surprised. Must have messed up somewhere but they didn't give me any details. Overall though, very fun interview process. Respect to the people who have the intelligence and ability to get the offers!

12/9/09

iluvhermione, was your third round similar to brotherbear's? -- brainteasers/market making etc. mind sharing the questions you got? its really baffling what these guys are looking for ..

12/9/09

their questions actually aren't that bad.

just do a lot of AIME/Math Counts type questions and really understand something about probabilities and market making and you should be fine.

12/9/09

Hey,

Trying to understand the how you should think about answering this question..

I'm thinking of a 10-digit number, where each digit represents the number of that ordinal number in the whole number. So, the first digit represents the number of 0's in the whole 10 digits. The second digit represents the number of 1's in the whole 10 digits. And so on. The first digit is not a '0.' What is my number.

Can someone explain how they got that answer? thanks

2/2/15

9000000

12/9/09

Sandy Weill nearly failed because he didn't care too much for his school work and partied too much. He coasted through his college years because he was expecting to lead his father's steel import business in Brooklyn. Right before graduating his parents divorced (father had a mistress) and his father told him that he had sold the business in the months before. It was def. the lowest part of his life.

2/2/15

Expect a lot of probability questions and brain teasers. They have a reputation for notoriously difficult interviews. Are you applying for their assistant trader job? The pay is shitty-around 40K base, which is nothing in NYC.

2/2/15

i'm surprised; i heard kids there make millions by the time they're 28; could just be rumor though. does anyone else have any insight?

2/2/15

28 is 6 or 7 years in. at a pretty respectable proprietary firm like Jane Street, you could conceivably be making that much if you're good. your first year would be spent learning the ropes, so yeah, of course its going to be shitty pay-wise.

another thing to consider is that not everyone at these places makes it through these trader assistant programs. Jane Street hires some really sharp guys, so they might have a higher retention rate, but for these prop shops, if they think you're useless, then they won't hesitate to dump you.

2/2/15

that seems really low; i would think it would at least be comparable with capital markets/trading positions at banks; is this true? or no, sorry i really had my hopes up regarding this interview, and i make much much more than 40k right now, so if this is what i have to look forward to, i think i might have to reassess things; thanks so much for all your help everyone

2/2/15

40K doesn't go far in NYC, but it's worth the sacrifice to go through a top prop firm training program. It takes time to learn this stuff. I'd recommend taking smaller pay now for greater reward a little later on.

2/2/15

if you go to a prop shop like susquehanna, drw, jane street, whatever, don't count on making very much when they are training you. you can make a lot of money as a trader though, but there is a chance they won't keep you if you don't meet their expectations. higher risk => higher reward

i will tell you right now that Jane Street is mad impressive. some sharp math geeks in their upper echelons.

2/2/15

Actually their pay is very much on par with banks (if not more when you factor in bonuses which are very substantial). They pay their first years very well which is why a bunch of guys I know headed there instead of BBs.

They have a very team based approach apparently. And their retention rate is very high because they hire only the sharpest guys out there (and thus the ridiculous interview reputation).

Good luck.

2/2/15

yes, 1st round is a lot of probability.
2nd round you also get some programming questions - i think they do most of their work on OCAML - so maybe read up on that.

2/2/15

Does Jane Street really pay that much money?
http://www.nytimes.com/2008/11/14/nyregion/14crawl...

"But it held no allure to Matt Yeager, a 24-year-old trader with Jane Street who is shopping for a two-bedroom apartment for $2 million to $3 million."

2/2/15

I would be surprised if he was paying for the room in all cash, but housing isn't a terrible investment at this point.

""The thing I dig is the bar across from the powder room," said Patrick Nichols. Twenty-seven and newly married, Mr. Nichols, a trader with Jane Street Capital, scribbled in a leather-bound notebook and snapped photos. He is looking to spend $2 million to $3 million on a two- or three-bedroom apartment. He said he did not know many people hurt by the slowdown, and he was not worried about losing his job.

"Anytime in the next six months would be a good time to find deals," he said. "I think there are a lot of panic sellers.""

"But it held no allure to Matt Yeager, a 24-year-old trader with Jane Street who is shopping for a two-bedroom apartment for $2 million to $3 million."

What's with all the Jane Street people in the interviews? I thought they avoided press coverage.

2/2/15

Well, obviously he isn't paying in all cash, but even at 20% down on a $2-3mm apt, that's 400-600k.

Good luck affording the maintenance/co-op fees on the place.

2/2/15

haha that picture of that Jane St. trader in the NYT is hilarious....reminded me of comic book guy from the Simpsons

2/2/15

http://img509.imageshack.us/my.php?image=mattvj9.jpg

isn't bright enough to block off his facebook. or just doesn't care. either way, amusing guy.

2/2/15

Hi everyone!

I am having a 2nd round interview soon - i ve got a pair of questions
am i supposed to be really good at programming?
what kind of programming questions are they going to ask?

thanks a lot!!!

2/2/15

jane st is 100k base with a 20k singing bonus for new graduate hires into the trading program, i don't know where you guys are getting your information from but it is incorrect

2/2/15

if it's for a 2nd round trader than no.

2/2/15

It is an internship and people say Jane Street want programming skills
So, what kind of questions can i expect? Something on OCaml?

2/2/15

JSC is VERY quant. expect brainteasers

Maybe I should drag around a toilet to show people that I AM THE SHIT.

2/2/15

Thanks! Ill study brainteasers hard and review programming courses i took.

2/2/15

I came into my first JSC interview with a heavy background in math contests and zero background -- none -- in finance or programming. I found the interviews to be manageable but still challenging.

2/2/15

Is this firm still doing well right now? Still growing and hiring people?

2/2/15

I am graduate student ( doing Ph.D. ) from a premier mathematical research institute in INDIA. The focus of my research is mathematical finance and its applications in stock-market, derivative pricing,hedge funding,and like. So, I also started doing CFA ( to gain more insight from pure finance persepective ). I have completed LEVEL 2 of the exam. I heard about JSC during one of the examinations of CFA. I wanted to know that can I apply for this company? I have already spent enough on my studies and now have support my family ASAP. So,what do you guys think - should I apply for this job? If yes, then tell me frankly about my chances of being selected and how much money will I be making?

Financial Modeling

12/11/09

I'm thinking of a 10-digit number, where each digit represents the number of that ordinal number in the whole number. So, the first digit represents the number of 0's in the whole 10 digits. The second digit represents the number of 1's in the whole 10 digits. And so on. The first digit is not a '0.' What is my number.

Can someone explain how they got that answer? thanks

So, the first thing I saw was that the sum of the digits has to be 10.
If the leading digit is6 or above, we need to have at least 2 ones (since we need a 1 for the 1-spot, and a 1 for the 6,7,8,9-spot).
This means that we need at least one number that is bigger than 1 that doesn't account for the leading digit.
So, the leading digit can't be 7,8,9.

6210001000 works.

There is no way I could do this in 30 seconds though. I did the AIME in 8th grade and throughout high school, and did the USAMO a couple of times, but I'm definitely not at the IMO level. I have an interview coming up, but my chances seem a little slim.

2/2/15

Use the search function, tons of threads

2/2/15

Given your math background, you should good for the probability. Other than that, expect a lot of stupid mental math questions, if it's on the phone go ahead and cheat and use a calculator, it's not like they know anyway, just don't be too quick to where they are suspicious. Then they'll hit you with a couple bran teaser type logical reasoning questions. Just be sure to talk out your thought process clearly, that's almost as important as getting the right answer with them.

Good luck, Jane Street is a great company, and they are one of the few that doesn't give a shit what year you are, if you do a good job, theyll take you even though you're a freshman

2/2/15

You're a freshman from a LAC, I doubt they'd go into too many technical questions. It'll be mostly fit, so be sure to nail those first and foremost

2/2/15
roymondito:

You're a freshman from a LAC, I doubt they'd go into too many technical questions. It'll be mostly fit, so be sure to nail those first and foremost

This is probably wrong. They'll ask math questions, just not questions about securities/finance.

2/2/15
roymondito:

You're a freshman from a LAC, I doubt they'd go into too many technical questions. It'll be mostly fit, so be sure to nail those first and foremost

i would also tend to disagree with this. almost every JSC interview ive heard about has been HEAVY in mental math and probability regardless of age. be prepared, and as someone had said, the search tool is huge for JSC, lots of good advice has been posted.

2/2/15
roymondito:

You're a freshman from a LAC, I doubt they'd go into too many technical questions. It'll be mostly fit, so be sure to nail those first and foremost

Like everyone else said already, this guy knows nothing about Jane Street. Be ready for a full on technical interview, and minimal fit stuff.

2/2/15

glassdoor.com and braingle.com

2/2/15

Hey macvsog,

I have a third round coming up. Are you still interviewing with them? Did you get to the 3rd/4th/final round?

What kind of questions do they like to ask? Is it the same with the first two rounds though progressively harder? Am I expected to have programming skills?

Thanks.

12/11/09

I've looked through this and previous JSC threads and the questions aren't that hard. Do the following:

1) Buy Arthur Benjamin's book on mental math
2) Take a introductory class in statistics
3) Take the computer science division's discrete maths course
4) Play poker/bridge to ace questions in later rounds

2/2/15

23 - 459?
Square root of 39?
What is 23 cubed?
What is 1/113 to 5 dec places?

If there is a 50% chance it rains on a weekday and 30% chance it rains on a weekend, what is a probability that it only rains on Wed and Sun in a given week.

Simple stats like above...

Stuff like that is common in 1st round

"Every man should lose a battle in his youth, so he does not lose a war when he is old"

2/2/15

They weed out the majority of people after the first round, but if you get past it, you'll probably go through 2-3 more (rarely do people get cut after 2nd and 3rd round).

2/2/15

i recently interviewed with Jane Street and past the 1st round. they started off by asking 3 mental math questions and asked simple prob questions like the expected number of heads you can get by flipping x coins, etc. nothing special. i was able to answer all problem in 10s after going through all glassdoor questions.

2/2/15

4 mental math questions. Stuff like 37 times 37. How many 27-cent stamps can you buy with $10, etc. Then he asked how confident (in a probability) I was that I got them all right, how confident I was I got the hardest one right, and how confident I was I got at least one wrong. After, he asked me a coin problem: What is the probability you get exactly 2 heads in 4 flips of a coin.

I found this on glass door and I was wondering about the confidence questions. What are they looking for in this?

For instance, the question about stamps, the answer is 37. If I give that answer and they ask how confident I am, should I just say 100%. Or are they looking for more than that?

2/2/15

I think usually when they ask that in a mental math, you got the number wrong

12/10/16

They always ask for intervals w/ confidence. Basic stats

12/11/09

4) Play poker/bridge to ace questions in later rounds

This makes me happy. Just got to get through the first few rounds lol

2/2/15

The final round is mostly fit, whereas the other rounds are all technical (math) getting harder each time around.
for the first few rounds hey ask you all math questions where you have to use logic to walk through the answers and they yell at you if you don't explain and just give them an answer

2/2/15
LadyEva:

The final round is mostly fit, whereas the other rounds are all technical (math) getting harder each time around.
for the first few rounds hey ask you all math questions where you have to use logic to walk through the answers and they yell at you if you don't explain and just give them an answer

Not sure if others had different interview experiences than the handful of data points I have, but all of the final rounds I have information about at JS were still pretty mathy. The questions were comparable or perhaps slightly easier on average than later phone rounds, but the context was different - faster pace thinking, adding in thoughts about risk and certainty/sources of error.

2/2/15

Good luck.

2/2/15

Hello guys,

I know that there were many posts about Jane Street interviews (for a quantitative trading summer internship) and that they focus on mental math and probabilities for the first round.

But the fact is that I am a student in France and I don't know how to prepare it. I didn' t find interesting books ..

If anyone could help me ..

Thanks

2/2/15

heard on the street is probably the best way to prepare for these kinds of math based interviews

12/15/09

Hi,
What are they asking in the first round - lots of small questions, so that you don't have enough time or the pace is not so important as with Optiver, etc?

2/2/15

Check out the brainteaser threads.

Banking > VC > Tech PE; PM me if you would like any advice I'm happy to help

2/2/15

I interviewed with JSC for a trading SA position. It is all brainteasers and maybe 1-2 fit questions. The type of questions you can expect are:

1) what is 61*14?
2) What is the expected value of rolling a die?
3) What is the expected value of rolling a die twice and taking the highest number?
4) What is the probability of flipping 2 or more heads if you flip a coin 4 times?

Just work a bunch of problems similar to those and you will be fine. Know binomial distribution and methods of counting.

2/2/15

just to check, for #3:

E(1 roll) = 3.5
for the second roll, there is a 1/6 chance each of rolling a 4, 5, and 6, which would result in incremental increases of .5, 1.5, and 2.5, respectively. (1/6)*(.5+1.5+2.5) = .75. So value is .75 + 3.5 = 4.25, correct?

2/2/15

Hmm never thought about it that way but the answer is 4.25.

E(1 roll) = 3.5, so you stop if you get a 4,5,6 and roll again if you get a 1,2,3.

So, assuming an unbiased die, you stop half the time and continue half the time. If you roll again, your expectation is again 3.5, but if stopped, then your expectation is 5. Simple conditional expectation.

Hence, E(2 rolls) = 1/2(3.5) + 1/2(5) = 4.25

1/8/17

your's and 'yesman''s solution missed the cases like (1,3) where 1 is rolled first and 3 next.

2/2/15

my answer is only true if you must decide whether to roll again or stop after the first roll. If you get to roll twice and take the highest number, then you need to find the expectation of X(max).

2/2/15

Let X=Xmax
Let Y=Xmin

Then draw out a joint probability distribution for X,Y and sum the Xs to find the distribution of X max:

X 1 2 3 4 5 6
P(X) (1/36) (3/36) (5/36) (7/36) (9/36) (11/36)

Which gives E(Xmax) = 161/36 = 4.472

2/2/15

First round was not bad at all although I was crazy nervous and over-estimated the problem's difficulty.

2/2/15

there are least 5, probably more. i'm locking this one. next time, please do a search before posting.

12/16/09

you won't have to worry about speed too much. its more problem solving based and relaying out your thought process

here were my experiences, hope its helpful!

1st round: some mental math like 45% * 110, 30 billion minus 71, etc. then some probability teasers which u can find through crack's interview book. so it's not too bad if you are relatively good at math. crack's book is a really good guide btw. (either that or doing AIME problems lol)

2nd round: questions that get a bit more tricky, like if we flip a fair coin until i hit HHT or u hit HTT, wat are the odds that i win? you may also get some confidence questions like "how confident are you in your answer" and "if i were to offer you this to that, would you accept."

3rd round:
a few questions on searching for a false item or multiple false items. think "find false heavy or light coin among x number of coins using scale" and that sort of thing. and then some more confidence questions.

i am not 100% sure about this, but I asked a couple of people who attended a jane street info session, and they said that the questions you get are geared more towards ur background. so depending on how much experience you've had in those things, its possible your questions will be tougher or easier!

2/2/15

i interviewed with them for summer. there are several threads on WSO so look around. get crack's book.

2/2/15

crack's book?

2/2/15

It's a book of quant fin/math interview questions. The guy's last name is crack.

2/2/15

heard on the street

2/2/15

know your probability

12/16/09

I've seen some Jane Street interview questions here: http://brainden.com/forum/index.php?/forum/7-new-l...

Either way, it will get you some good practice for this kind of interview.

  • Child Please.
2/2/15
2/2/15
12/16/09
12/17/09
10/22/10
Add a Comment
WallStreet Prep Master Financial Modeling