Jane Street’s Trading Interview: What to Expect

Michael, a trader who joined Jane Street in 2018, and Megan, a trading recruiter who joined in 2008, explain the purpose and structure of the firm’s trading interviews. They also discuss common misconceptions about what candidates need to know and how they are evaluated.

The process tests foundational trading skills, including quantitative thinking, communication, teachability and carefulness. The speakers say the questions require neither prior finance knowledge nor advanced university mathematics. Even complicated scenarios can be analyzed without especially high-level techniques; intuition for probability and expected value is particularly useful.

The process begins with two or three phone interviews and may lead to up to a day of interviews in person or over Zoom. Traders conduct the interviews. Candidates may use pen and paper but are asked not to use a computer or calculator.

The speakers strongly encourage candidates to think out loud. Interviewers want to understand the reasoning, not simply whether the final answer is right; some questions may not have one right answer. Speed is useful, but accuracy matters more, and candidates can take time to check whether an answer makes sense.

Early interviews generally use simpler problem-solving techniques and basic probability. Later questions become more complex and open-ended. The intended experience is a conversation about an interesting problem, closer to working together on a trading desk than taking a test.

For instance, a question might involve playing a game against someone whose actions cannot be predicted. Finding an optimal strategy may be very hard, so a candidate can make assumptions, propose a reasonable first strategy and then look for ways an opponent could exploit it.

A useful general approach is to reduce an unsolved problem to one you can solve. The speakers suggest simplifying assumptions, trying smaller cases and working backward. These steps provide a starting point for refining an answer together.

One misconception is that success requires extraordinary mental arithmetic. The speakers say they do not care whether a candidate can quickly multiply 37.2 by 93. They do value numeracy: for example, intuitively recognizing that the average of numbers from 1 to 1,000 is roughly 500, or that squaring a number between zero and one makes it smaller.

Another misconception is that one wrong statement automatically means failure. The questions can be difficult, and interviewers are interested in how candidate and interviewer work together on a hard problem. They consider communication, intuition, tenacity and teachability as well as quantitative ability.

Finally, not making it through the process one year does not automatically prevent a later interview. Decisions are made case by case, and the speakers say some Jane Street traders—including one of them—did not succeed on their first attempt. They point candidates to a mock interview and a probability and markets guide for further preparation.