How to Prepare for Quant Interviews

Understanding the structure of quant interviews helps you prepare systematically. While every firm is different, the typical process at top quant firms follows this pattern:

• Round 1 — Online Assessment / Phone Screen: Usually a math/probability quiz (timed, 30-60 minutes) or a coding challenge. Some firms use HireVue video interviews. This is a filter — passing requires solid fundamentals but not brilliance. At firms like Jane Street and Optiver, this may include mental math speed tests.
• Round 2 — Technical Phone Interview: A 45-60 minute call with a quant or trader. Expect 3-5 probability questions, mental math, and possibly a market-making scenario. The interviewer wants to see how you think, not just whether you get the right answer.
• Round 3 — Superday / On-Site: 3-5 back-to-back interviews, each 45-60 minutes. Topics vary:
  • Probability & statistics (almost always)
  • Brain teasers & puzzles (common at prop shops)
  • Coding (algorithms, data structures, or quantitative coding)
  • Market knowledge (market-making games, options pricing, current events)
  • Behavioral / fit (why trading? why this firm? teamwork examples)
• Round 4 — Final Round (some firms): Senior trader or partner interview. More conversational, testing cultural fit and judgment under pressure. May include impromptu market scenarios or estimation problems.

The entire process typically takes 3-6 weeks from first contact to offer. Some firms (especially during recruiting season) move faster.

Technical preparation is the core of your interview prep. Here's what to focus on, roughly in order of importance:

1. Probability & Expected Value (40% of prep time)

This is the single most important topic. You need to be fluent in:

• Conditional probability and Bayes' theorem
• Expected value calculations and linearity of expectation
• Combinatorics and counting arguments
• Random walks and Markov chains
• Common distributions (normal, Poisson, geometric, binomial)

See our probability questions guide for worked examples and study resources.

2. Mental Math (15% of prep time)

Many firms test mental arithmetic speed. You should be able to:

• Multiply two-digit numbers in your head quickly
• Estimate square roots, logarithms, and powers
• Convert between fractions, decimals, and percentages instantly
• Add and subtract multi-digit numbers rapidly

Practice daily with apps like Zetamac, Rankyourbrain, or simple flashcards. Aim for at least 15 minutes per day of mental math drills.

3. Brain Teasers & Logic Puzzles (15% of prep time)

Brain teasers test creative problem-solving and comfort with ambiguity. Common types include weighing puzzles, logic riddles, optimization problems, and lateral thinking questions. See our dedicated guide for examples and strategies.

4. Programming (20% of prep time)

For quant trader roles, coding interviews focus on quantitative problems rather than pure algorithms. Typical questions include:

• Simulating a dice game or card game and computing expected values
• Implementing a simple pricing model or backtesting framework
• Data manipulation and analysis (pandas, numpy)
• Classic algorithms (sorting, searching, dynamic programming) at a medium difficulty level

For quant developer roles, expect harder algorithm questions comparable to LeetCode medium-hard.

5. Market Knowledge (10% of prep time)

You should understand:

• How market making works and the concept of bid-ask spread
• Basic options Greeks (delta, gamma, theta, vega)
• Current market events and their implications
• Simple estimation and Fermi problems ("What's the daily volume of SPY?")

Don't neglect behavioral questions — they matter more than many candidates realize. Firms want to know that you'll be a good teammate, handle stress well, and are genuinely excited about the work.

Common behavioral questions:

• "Why do you want to be a quant trader / researcher / developer?"
• "Why this firm specifically?" (Do your research — know what makes each firm different)
• "Tell me about a time you worked on a team and there was a disagreement."
• "Describe a project where you had to learn something new quickly."
• "What's a mistake you made and what did you learn from it?"
• "What do you do outside of school/work?" (They want to see intellectual curiosity)

Tips:

• Have 3-4 polished stories ready that demonstrate quantitative thinking, teamwork, and learning from failure.
• Be specific about why you want the role and why the specific firm. Generic answers ("I like math and making money") are instant turnoffs.
• Show genuine enthusiasm for markets and trading. Mention a trade idea, a market event that fascinated you, or a paper you read recently.
• Be honest. Quant interviewers have excellent BS detectors.

Here's a structured timeline for interview preparation. Adjust based on your current level — if you're already strong in probability, shift time to weaker areas.

Weeks 1-2: Foundations

• Review probability theory fundamentals (3-4 hours/day)
• Start daily mental math practice (15-20 min/day)
• Read "A Practical Guide to Quantitative Finance Interviews" (Green Book) cover to cover
• Begin coding practice — solve 2-3 quantitative coding problems per day
• Start reading financial news daily (WSJ, Bloomberg, FT) — 15 min/day

Weeks 3-4: Problem Solving

• Solve 10-15 probability problems per day, timed (5 min per problem max)
• Work through brain teaser collections (Heard on the Street, Crack)
• Implement 2-3 simple trading strategies in Python (moving average, mean reversion)
• Study options Greeks and basic derivatives concepts
• Practice explaining solutions out loud (record yourself or practice with a friend)

Weeks 5-6: Mock Interviews

• Do 2-3 mock interviews per week with peers or mentors
• Practice market-making games (simulate bid/ask scenarios)
• Refine behavioral stories — practice delivering them naturally
• Review weak areas identified during mocks
• Start timing full interview sessions (45-60 min blocks)

Weeks 7-8: Final Polish

• Focus on speed and confidence — review previously solved problems
• Do 1-2 full mock superdays (4+ hours of continuous interviewing)
• Research specific firms you're interviewing with — culture, strategies, recent news
• Prepare questions to ask interviewers (show genuine curiosity about the firm)
• Rest and maintain confidence — diminishing returns from last-minute cramming

Want a personalized study plan? Book a free consultation and we'll assess your current level and build a targeted prep strategy.

After working with hundreds of candidates, we see the same mistakes repeatedly:

• Starting too late. Four weeks of focused prep is the minimum. Eight weeks is ideal. Starting one week before interviews is a recipe for failure at top firms.
• Neglecting mental math. Many candidates ace the probability theory but stumble on basic arithmetic under pressure. Daily practice is essential — it's a skill, not a talent.
• Memorizing without understanding. Interviewers will twist familiar problems into unfamiliar variants. If you've memorized the answer to "expected flips for two heads in a row" but can't solve "expected rolls for three sixes in a row," your preparation is too shallow.
• Not practicing out loud. Reading a solution and explaining it verbally are completely different skills. You need to practice articulating your thought process clearly, including your wrong turns and corrections.
• Ignoring behavioral questions. "I'll just be myself" is not a strategy. Prepare specific stories, research the firm, and practice delivering your answers naturally.
• Applying to too few firms. Even strong candidates get rejected — the process has inherent randomness. Apply to at least 8-12 firms to maximize your chances.
• Not doing mock interviews. Solving problems alone is not the same as solving them under interview conditions. Mock interviews are the single most effective prep activity.

Avoid these mistakes and you'll be ahead of 80% of candidates. Combine disciplined preparation with genuine passion for quantitative problem-solving, and the odds are very much in your favor.