After going through the interview process, the OP shared the final round interview experience with readers of WSO. Check it out below.
Jane Street Capital Interview Process
Before the interview I went through five phone interviews before they invited me down, and I think they would have kept going except that I had an exploding offer coming up so I told them its final round or nothing. Every time I thought I had finally messed up the interview to the point where they wouldn't invite me back, but every time hr contacted me with the next date. When they say 'we aren't looking for the right answer so much as how you think about a problem', they mean it.
Preparation for the Final Round Jane Street Interview
Before the final round they send you a sheet outlining the basics of trading terminology. What bid and ask mean, as well as how to properly phrase that you would like to make a trade and at what price. My first pearl of wisdom is to study the shit out of this sheet.
If you have had trading experience before, great, but most applicants to Jane Street are, like me, math or other STEM majors so have not seen these terms or if they have certainly have not used them in a real time environment. As a note: I had taken finance courses and knew what these definitions actually meant, but there is a HUGE difference between being able to pass an econ exam and being able to rattle off a trade without thinking about it.
The last thing you want is to be committing mental capacity to figuring out if you want to give your bid or your ask price first when you should be fully committed to doing three digit fraction multiplication. Even worse, if you get confused and phrase the trade incorrectly the interviewer will not be afraid to crush you and take a highly unfavorable trade (for example by selling to you at the price you meant to give as your ask price). You should have a couple days between getting this sheet and the final round, use that time and don't wait until you were sitting around in the hotel the night before like me.
What Happens At A Final Round Jane Street Capital Interview?
At the final round itself you are given 100 poker chips at the start of the day. Over the course of the next 4-6 hour long interviews (I only had four, but I think that's because I got cut after four - there were still people interviewing as I left) you have to use the chips to make bets on scenarios given to you. Some sources claim these scenarios can be as simple as 'make a market on the temperature in the room', I didn't get these questions and I'm guessing that they are reserved for internship interviews. I got much more difficult ones, that require a decent amount of math. You will need to use the trading terms to bet on the results you get. There is probability involved (for example a deck of cards or non-six sided die), so the more astute of you will notice that a better candidate may end up with fewer chips than one who bet and got lucky - don't worry Jane Street is fully aware of this and judge you based on what you bet and why, not how much you win. Therefore, the actual number of chips you end up with is irrelevant (to a degree -see below), so if you have 20 chips after getting very unlucky on reasonable bets, don't try to win it all back thinking you are below some magic cutoff, there really isn't one. It is best to just ignore the existence of the chips to the extend you can and think about each problem as just an isolated probability/brain teaser problem.
The biggest single thing to remember about your chips is to never go all in. They tell you at the start of their interview that in their job they make positive expected value bets, but to never do so if there is a chance of being wiped out. Therefore, keep in mind: if you are 99% sure of something it means that you are willing to bet 99 of your chips just to get one chip, and even if what you're betting on is a coin flip with only heads, it’s not acceptable to take that bet (extreme example, the in-interview examples are much more subtle). This means that if you end up with single digit chips you will almost certainly not get an offer, since you bet in a way that 'wiped you out' (note I ended up with 87 and still didn't get an offer).
Not every interview depends on the chips - some are straight math questions. All the more reason to just ignore the chips since you don't want to be thinking "shit I only have 43 chips" during an interview that doesn't concern the chips at all - always stay focused.
Interview Questions for Jane Street Capital
In terms of specific questions they ask: I would recommend going on glassdoor and looking up interview questions for Jane Street and maybe some other prop shops (ex. SIG). I actually encountered some very similar to the ones I had seen there, but they have enough new material that you will not be able to memorize your way through the interview.
Jane Street Brainteasers
Finally, they do ask an unsolvable question (or rather, one that you need a PhD in probability to answer), so yeah those rumors are true. Not gonna tell you what it is (where's the fun in that?), but I had seen it online before my interview. The point of the questions is not to get it right, but to bet chips on how long you think it will take you to answer it (the prompt is deceptively easy). Now remember, if you bet on a 99% confidence interval, it means you are technically saying you would bet 99 chips that you will be able to solve it for the chance to win one chip.
JSC Interview Process
Jane Street's interview process can be intimidating, and Jane Street describes how to prepare below. They also offer a guide to research and trading roles that we have attached below.
Source: https://www.janestreet.com/2017/05/18/probability-markets/
Read More About Jane Street Capital in Our Company Database.
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| Jane Street Interview Guide 1.22 MB | 1.22 MB |
So basically you are refusing to provide what you were looking for when you created this topic to start with. And "outline general process" which can be found somewhere else.
How useless and unhelpful is this ?
I got to final round 1 year ago, i made some mistakes so didn't get an offer and can't remember all the questions and it would take far too long, but here is a detailed "game". All day is made of these games, with some mix of the usual brainteasers/questions you get in the telephone rounds.
"Process" : You get 100 chips, and for the next 4-6 interviews, you make "bets" and "markets" on different games they show you. 1st set is a "training" set, meaning that they say they won't take it into account for the purpose of assessing your performance.
A typical "game" is : you have 4 cards picked randomly from a deck face down. Then they give you a set of "bets" example : -if the sum of hearts is higher than XX you get 1 chip, if it is lower you lose 2 chips. -if the first 2 cards are black you make 4 chips, else you lose 5. etc etc... And "make markets" question : - make me a 5 wide market on the the square of the number of red cards. giving size as well. So for example : if you say 20@25 with 2 size. It means that the interviewer will be able to trade with you at these levels, for a max size of 2. (So for each point of different you lose/make 2 chips). Once you have picked all the bets you like, and made your markets, the interviewer will acknoledge your bets, and trade on your markets. You then reveal 1 or 2 cards for example, he then asks you to update your markets given the new information, he will then trade again with you. And on bets, they give you an opportunity to "exit" the bet for a fixed gain or loss, and you need to decide if you keep the bet or exit. You then reveal all cards and settle all bets / markets. Something really important is you need to NEVER be put in a position where you can lose everything if a "bad" scenario happens. As in sometimes your interviewer will play "dumb", and if you are not paying attention, he can give you some huge size at apparently very unfavorable odds for him, so you should be happy heh ? Well not really because if an unlucky scenario happens, it doesn't matter that you making loads of chips in expectation, you are still wiped out or almost. So you need to always keep track of your risk and potential max loss / etc... It can get a bit out of hand if you get some huge position and realize it too late and try to exit. The interviewer will screw you very hard, giving some very bad exit trades that you are basically forced to take to not risk being bankrupt when cards are shown.
Anyway this is already a very long post but in any case, i remember having a lot of fun in these interviews.