Interview preparation

Jane Street Interview Guide

Welcome to your comprehensive guide for navigating the interview process at Jane Street. As one of the premier trading firms globally, Jane Street's selection process is both challenging and thorough, designed to identify the best candidates for their dynamic trading team. This guide aims to demystify each step of the Jane Street interview journey, providing you with the insights and strategies needed to make a strong impression.

Joining Jane Street requires demonstrating excellence across various competencies through a multi-stage interview process. Here’s what you can expect:

  1. Application Review
  2. Phone Interviews
  3. Final Round

Each of these stages targets specific skills and attributes, ensuring a well-rounded evaluation of your fit for the firm. In this guide, you’ll find a breakdown of each stage, along with expert advice on how to prepare effectively and stand out from the competition.

Prepare to embark on a rigorous yet rewarding journey towards potentially joining one of the most esteemed trading firms in the industry. Let's dive into the specifics and equip you with the tools for success.

Jane Street office

Stage 1: Application Review

Overview: Once you submit your application, it is reviewed by a human instead of a machine-automated evaluation (this is not the case for many other trading firms!). Typically, candidates receive responses from Jane Street within a week.

Before you submit your application, make sure to take a good look at this video detailing the Jane Street interview process and this page about Jane Street's culture.

Preparation Tips:
  • Tailor Your Resume: Highlight relevant experiences and skills that align with the trading role.
  • Cover Letter: Craft a compelling cover letter that explains why you want to work at Jane Street and your interest in trading.

Stage 2: Phone Interviews

Overview: The interview process begins with two to three phone interviews, focusing on foundational skills through conversational questions. No prior finance knowledge or advanced math is required. These interviews focus on foundational skills and thinking processes.

Key Points:
  • Basic Problem-Solving and Probability: Early interviews focus on simpler problem-solving techniques and basic probability concepts.
  • Pen and Paper Only: You can use pen and paper but not computers or calculators.
  • Think Out Loud: Thinking out loud is encouraged to understand your thought process.
  • Accuracy Over Speed: Speed is less important than accuracy and clarity of thought.

Usually, a series of games are played in this round, which go roughly as follows.

Series of Three Games:

  1. General Setup:
    • You start with the first game.
    • Your end score in the first game is your starting score for the second game.
    • Your end score in the second game is the starting score for the third game.
    • You will discuss the game with one or two traders who will guide you.
  2. Game 1 – Casino Game, Sports Betting:
    • Objective: Maximize your chips by betting on sports outcomes over multiple rounds.
    • Setup: 100 participants, each starting with 100 chips.
    • Rounds: Multiple rounds with weekly bets on two competing teams (Team A and Team B).
    • Strategy: Understand odds, use historical data, and manage chips wisely.
  3. Game 2 – Dice Game:
    • Objective: Maximize your chips by making strategic bets based on dice rolls.
    • Setup: Single participant game starting with chips from the first game.
    • Rules:
      • If the die roll is even (2, 4, 6), you win 3 chips.
      • If the die roll is odd (1, 3, 5), you lose 2 chips.
    • Strategy: Evaluate risk, consider chip count, and adapt to rule changes prompted by questions before each roll.
  4. Game 3 – Divide and Conquer:
    • Objective: Achieve the highest percentile rank among 100 armies by strategically dividing soldiers across 10 castles.
    • Setup: 100 participants each commanding an army of 100 soldiers.
    • Strategy:
      • Conduct experiments with small numbers of soldiers to gather data.
      • Use gathered insights to make final strategic allocations.
      • Balance information costs with potential benefits.

It is these games that are played most often, although we do hear occasionally that these games are replaced by (very hard!) brainteasers.

Preparation Tips:

Stage 3: Final Round

Overview: Candidates who pass the phone interviews are invited to the Final Round, a full day of interviews either in-office or virtually via Zoom. This stage involves a series of technical interviews conducted by current traders and emphasizes a deeper evaluation of problem-solving abilities and strategic thinking. This day also contains a HR element where the focus is on your cultural fit, background and motivation.

HR Stage:

Technical Stages:

Format:
  • Pen and Paper Allowed: Computers and calculators are not allowed.
  • Conversational Approach: Interviews are designed to feel more like conversations rather than tests.
  • Think Out Loud: Demonstrating your thought process is crucial.

Content:
  • Early Questions: Focus on basic problem-solving and probability concepts.
  • Later Questions: Involve more open-ended, complex scenarios requiring strategic thinking.

Selection of Games Played in the Interview:

Game 1: Basic Casino Game
  • Setup: A 20-sided die (numbers 1 to 20) starts with the number 1 facing up. You have 100 rounds.
  • Options per Round:
    • Roll the die to get a new number.
    • Take money equal to the current face value of the die.
  • Objective: Maximize your earnings.
  • Strategy:
    • Initial: Roll the die until you hit a 20, then take 20 for the remaining rounds.
    • Adjusted: Consider rolling until you hit an 18, 19, or 20 to balance risk and reward better than aiming for just a 20.

Game 2: Die Removal After Taking Money
  • Setup: Same 20-sided die and 100 rounds.
  • New Rule: When you take money, the die is removed, and you must roll it again before taking money again.
  • Strategy:
    • Initial: Accept the top half of numbers (11 to 20).
    • Adjusted: Consider lower numbers (like 6 or higher) to balance the number of rolls and the payout per round.

Game 3: Casino Plays Against You
  • Setup: Same 20-sided die and 100 rounds.
  • New Rule: After you take money, the casino can choose to re-roll the die to minimize your earnings.
  • Strategy:
    • Initial: Accept numbers above a certain threshold.
    • Adjusted: Determine the equilibrium point where neither you nor the casino has an incentive to re-roll (approximately around 10).

Problem-Solving Techniques:
  • Simplifying Assumptions: Make simplifying assumptions to tackle complex problems.
  • Smaller Cases First: Try smaller cases to build up to the full problem.
  • Work Backwards: Use a backwards approach to solve problems.

General Strategies for the Interview:
  • Understand the Problem Thoroughly: Clarify any ambiguities in the problem statement before diving into solving it.
  • Think Aloud: Verbalizing your thought process helps the interviewer understand your approach and provides opportunities for hints or corrections.
  • Iterative Problem Solving: Start with a simple strategy and refine it based on expected values and further analysis.
  • Consider Edge Cases: Think about how different thresholds or strategies affect the overall outcome.
  • Collaborative Approach: Treat the problem as a conversation, iterating and improving based on feedback and further insights.

Preparation Tips:
  • Technical Knowledge: Brush up on probability and basic mathematical concepts.
  • Research: Understand Jane Street’s culture and values, know what they do and be prepared to discuss how you would contribute to Jane Street.
  • Stay Calm Under Pressure: Keep your composure and approach each problem methodically.
  • Effective Communication: Clearly explain your thought process and reasoning.
  • Show Confidence: Display a relaxed yet focused demeanor to show you can handle high-pressure situations.
  • Work Methodically: Break down complex problems into manageable steps and check your calculations.
  • Practice Under Simulated Conditions: Replicate interview conditions during your preparation to get accustomed to performing under similar stress.

Common Misconceptions

The Jane Street trading interview is a little bit different to that of other trading firms, and there are a few common misconceptions about the Jane Street interview process that you need to be aware of.

Misconception 1: You Need to Be Good at Mental Math: You don't need to perform complex calculations quickly at Jane Street interviews. What matters more is your numeracy and intuitive understanding of numbers.
Misconception 2: Saying Something Wrong Means Automatic Failure: Jane Street Interviewers prioritize your thought process and problem-solving approach over immediate correct answers.
Misconception 3: One-Time Failure Means No Future Opportunities: Failing once doesn’t disqualify you from reapplying at Jane Street. Many successful traders at Jane Street didn’t make it through the process on their first attempt.

To help candidates prepare, Jane Street offers additional resources that are worth taking a look at:

Closing Remarks

Preparing for the Jane Street interview process demands a strategic and thorough approach. This guide equips you with resources to practice specific tests, master behavioral interviews, and develop the analytical and strategic thinking needed for technical interviews and final round challenges.

One common misconception is that candidates need to get everything right in the Jane Street interview. However, Jane Street is more interested in your approach, your ability to communicate effectively, and your creative thinking. They value how you tackle problems, articulate your thought process, and adapt to new information.

Success at Jane Street requires a blend of sharp intellect, strategic insight, and a genuine passion for trading, alongside a personality that resonates with their culture. Approach each phase with diligent preparation, a mindset geared towards continuous learning, and an authentic display of your skills and character.

Many underestimate the intense preparation needed for Jane Street's competitive interview process. While the firm selects only the best, excelling isn't about perfection. It's about demonstrating your problem-solving skills, adaptability, and how you can contribute to Jane Street’s innovative environment.

Regardless of the outcome, the journey through the Jane Street interview process can be both challenging and rewarding. Each interview stage is an opportunity to showcase your potential, your unique approach, and how you align with Jane Street’s values and goals.