Interview
A Jane Street Trading Mock Interview with Graham and Andrea
- The interview process is expected to center on a collaborative, challenging quantitative problem consuming most of the allotted time, with candidates required to think out loud and clarify constraints which may take one to two minutes to establish.
- Candidates are not expected to perform extensive algebra to maximize functions but should instead identify the threshold where expected value exceeds a baseline, with specific optimizations suggesting acceptance of rolls of six or higher in standard scenarios.
- In a modified game where the die is removed upon taking money, a strategy accepting the top half of numbers (11–20) yields approximately $511 over 33 cycles, compared to a baseline of $525; a casino-player variant suggests an equilibrium threshold between 10 and 11, yielding roughly $775 over 50 cycles if both parties adopt this standard.
- Adjusting the casino-player threshold to 8–20 is predicted to increase earnings to $910, while alternative strategies accepting 19–20 require around 10 rounds for ~$1750, accepting 18–20 takes under seven rounds for ~$1767, and accepting 17–20 averages five rolls per sequence for ~$1757.
- The optimal threshold for the casino-player variant is anticipated to fall between the tested strategies, and candidates who are already traders are expected to perform well due to prior experience with similar problems rather than general intelligence alone.
- Interviewers anticipate candidates will feel they could not necessarily replicate the speed of the demonstrated progress and should not be discouraged, while the interview will likely conclude with a recap and an opportunity for the candidate to ask questions about the firm or internship.