What the firm says it is looking for
Jane Street is unusually direct about this, and it is worth taking at face value rather than second-guessing. On its trading interviews page the firm says the interview "will feel a lot more like a conversation than a quiz" and "won't require previous knowledge of finance or involve any complicated math, such as what you might learn in a higher-level math course in college."
That is a genuinely load-bearing statement. It means the marginal hour is better spent on clean probabilistic reasoning and on explaining yourself out loud than on memorising derivations or reading about markets.
The firm describes the candidates it hires as "curious, organized, and open-minded", says they "approach interview questions thoughtfully and collaboratively", and adds that most importantly they are "humble, pleasant to work with, and open to feedback."
Its own four tips for the interview are worth quoting in full, because they double as a description of how the questions are marked:
- "Approach the problem methodically."
- "Communicate clearly."
- "Correct your mistakes."
- "Ask why."
The firm also states that "asking great questions is more important than knowing all the answers."
The shape of the process
Jane Street describes an initial phone stage followed by in-person interviews for the final round, and notes that "the structure for our interviews may vary by discipline" - so a trading pipeline and a technology pipeline are not the same process, and preparing for the wrong one is a real and avoidable mistake.
For the final round it lists the ground the questions cover: "problem solving, probability and statistics, coding (in any language of your choice), data analysis, and general interests." Interviews are conducted by quantitative traders.
On logistics, the firm says phone interviews run during local business hours Monday to Friday, that video alternatives are available on request, and that it aims to give feedback within a week of an interview.
For technology roles it asks for coding in a language of your choice and says OCaml experience is not expected - a point worth knowing, since the firm's public association with OCaml leads a lot of candidates to prepare for the wrong thing.
What that means for preparation
Three things follow from the above, and they are the reason this page exists rather than a list of trivia.
Reason out loud, deliberately. "Communicate clearly" and "correct your mistakes" are not soft-skill garnish next to the maths - they are two of the four things the firm names. A correct answer arrived at silently is a worse performance than a slightly wrong one narrated well and then fixed. Practise saying what you are doing while you do it, which is uncomfortable at first and stops being so quickly.
Do not study finance. The firm says twice, in two places, that it does not test it. Time spent on options theory or market structure for this particular process is time not spent on probability and expected value, which it does test.
Get fast at the arithmetic anyway. "Complicated math" is disclaimed; quick, accurate mental arithmetic under mild pressure is a different thing and remains useful across every trading-side process in the sector.
Practise the same formats
The question sets below are ours - written by us, in the formats this process is reported to use. They are not Jane Street's questions, and nothing here reproduces any part of its assessment.