The Ultimate Quant Interview Guide

Breaking into quantitative finance is notoriously difficult. The acceptance rates for top firms like Jane Street, Citadel, and Hudson River Trading are often lower than 1%. However, the interview process is structured and predictable. With the right preparation, you can significantly increase your odds.

1. Understanding the Roles

Before diving into prep, it's crucial to understand the different tracks. "Quant" is a catch-all term that usually refers to three distinct roles:

• Quantitative Trader (QT): Focuses on making trading decisions, managing risk, and understanding market mechanics. Interviews heavy on mental math, probability, and betting games.
• Quantitative Researcher (QR): Focuses on building mathematical models and finding signals in data. Interviews involve statistics, data analysis, and sometimes machine learning.
• Quantitative Developer (QD): Focuses on building the infrastructure for trading. Interviews are similar to FAANG SWE interviews but with a focus on C++, low-latency systems, and OS internals.

Resumes That Get Interviews

Quant recruiters spend about 6 seconds on a resume. Here is what they look for:

• Competitions: Putnam Fellow, USAMO, IMO, IOI medals. These are the golden tickets.
• GPA: Unlike Tech, GPA matters. 3.8+ is the safe zone.
• Keywords: "Stochastic Calculus", "Time Series Analysis", "C++17", "Low Latency".
• Projects: Don't just list class projects. Build a trading bot (even a simple one). Backtest a strategy on QuantConnect. Show interest in the markets.

2. The Interview Process

Most firms follow a similar funnel. Here is what you can expect:

3. Key Topics to Master

Probability & Statistics

This is the bread and butter of quant interviews. You need to be comfortable with:

• Expected Value (EV): "What is the fair value of this game?"
• Conditional Probability: Bayes' Theorem applications.
• Combinatorics: Permutations, combinations, and path counting.
• Distributions: Normal, Binomial, Poisson, and Uniform distributions.

Mental Math

Speed and accuracy are proxies for how well you can handle pressure. You should be able to:

• Multiply 2-digit by 2-digit numbers (e.g., 23 * 57) in under 10 seconds.
• Estimate square roots and fractions quickly.
• Perform quick fractional arithmetic.

Market Making & Betting

Interviews will often simulate a market. "Make me a market on the population of New York City."

You need to understand:

• Bid-Ask Spread: Why it exists (inventory risk, adverse selection).
• Confidence Intervals: Setting widths based on uncertainty.
• Updating Priors: Integrating new information into your market.

4. Recommended Study Plan

If you have 4 weeks to prepare, here is how we recommend splitting your time:

Conclusion

The path to a quant offer is challenging but manageable. It requires consistent practice and a deep understanding of probability and markets. Start small, track your progress, and simulate interview conditions as much as possible.