What Makes Optiver Interviews Different
Optiver's interview process is one of the most demanding in the trading industry. Unlike most quant firms that lead with probability puzzles and coding tests, Optiver opens with a timed mental arithmetic exam that eliminates roughly 80% of applicants before they ever speak to a human. If you can't multiply three-digit numbers in your head at speed, you won't get past the first round.
Founded in Amsterdam in 1986, Optiver is a global market maker that trades on virtually every major exchange. They handle millions of transactions daily across equities, options, ETFs, bonds, and commodities from offices in Amsterdam, Chicago, Sydney, London, and Shanghai. The firm is known for its engineering-driven culture and its obsession with speed - both in execution latency and in how fast its people can think.
This guide covers the full interview process, the types of questions you'll face, and how to prepare. If you're also applying to other quant firms, our quant interview questions guide covers broader preparation across the industry.
The Optiver Interview Process
The full process typically takes 4 to 8 weeks from application to offer, though it can move faster for strong candidates. Here's the standard pipeline:
Stage 1 - Online Numerical Test (Week 1) An 8-minute timed test with 80 mental arithmetic questions. You'll add, subtract, multiply, and divide numbers with increasing difficulty. The pass rate is low - Optiver expects near-perfect accuracy at very high speed.
Stage 2 - Phone Screen (Week 2-3) A 30 to 45 minute call with a recruiter or team member. Expect a mix of motivational questions ("Why Optiver? Why market making?") and light technical questions. For trading roles, you may get probability questions or a quick mental maths drill.
Stage 3 - Assessment Day (Week 3-5) A half-day at the office (or virtual equivalent) with multiple rounds. This typically includes a harder maths test, a trading simulation or market making game, a technical interview (probability, statistics, or coding depending on the role), and a behavioural interview.
Stage 4 - Final Round (Week 5-8) Senior interviews focusing on trading intuition, cultural fit, and more advanced technical problems. For trading roles, expect deeper questions on options pricing, risk management, and how you handle uncertainty.
Optiver moves quickly once they're interested. If you don't hear back within a week of any stage, it's reasonable to follow up.
The Mental Maths Test
This is the part everyone talks about - and for good reason. Optiver's online numerical test is a timed sprint through 80 arithmetic questions in 8 minutes. That's 6 seconds per question. The questions start simple and escalate:
- Easy: 7 + 13, 45 - 18, 8 × 6
- Medium: 23 × 17, 456 + 789, 1200 / 48
- Hard: 67 × 43, 8.5 × 14.4, 3456 - 1789
You need both speed and accuracy. Getting 60 out of 80 correct is generally considered a pass, but competitive candidates score 70+. The test is adaptive at some stages, meaning it adjusts difficulty based on your performance.
Mental Maths Practice Questions
Try these under timed conditions - give yourself 6 seconds each:
- 37 × 13 = ? Break it down: 37 × 10 = 370, 37 × 3 = 111, total = 481
- 84 × 26 = ? Use: 84 × 25 = 2100, 84 × 1 = 84, total = 2184
- 1728 / 12 = ? 12 × 144 = 1728, so the answer is 144
- 456 + 378 = ? 456 + 400 = 856, minus 22 = 834
- 63 × 47 = ? Use: 63 × 50 = 3150, minus 63 × 3 = 189, total = 2961
- 2.5 × 3.6 = ? Think: 25 × 36 = 900, move decimals = 9.0
- 5600 / 35 = ? 35 × 160 = 5600, so 160
- 88 × 12 = ? 88 × 10 = 880, 88 × 2 = 176, total = 1056
The key technique is to decompose problems into easier parts. Multiply by rounding to the nearest 10 or 25, then adjust. For division, ask yourself what multiplied by the divisor gives the dividend.
Roles and How Interviews Differ
Optiver hires across four main technical tracks. The core arithmetic and probability testing is common to all, but the later rounds diverge significantly.
Trader
The most competitive track. After the maths test, traders face probability questions, options pricing theory, market making simulations, and extensive trading games. Interviewers look for quick decision-making under uncertainty, intellectual curiosity, and composure. You don't need a finance degree, but you do need strong quantitative reasoning and a willingness to take calculated risks.
Quantitative Researcher
Quant researchers get deeper statistical and mathematical questions. Expect time series analysis, regression, hypothesis testing, and potentially questions on signal processing or machine learning. If you're interested in this path, our guide to becoming a quant covers the educational background you'll need.
Software Engineer
Software engineers face standard algorithmic coding interviews alongside the mental maths test. Expect data structures, algorithms, system design, and questions about low-latency programming. C++ and Python are the primary languages. Optiver cares deeply about performance-critical code - you may be asked about cache behaviour, memory allocation, or lock-free data structures.
FPGA Engineer
A more specialised track focusing on hardware description languages (VHDL or Verilog), digital logic design, and low-latency networking. These interviews are highly technical and specific to the domain.
Types of Questions You'll Face
Beyond the initial maths test, Optiver interviews cover several question categories depending on your role.
Probability and Expected Value
These come up in every technical round for trading and research roles. They test whether you can reason about uncertainty quickly and correctly. Our probability fundamentals article covers the essential theory.
Example: You roll two dice and multiply the results. What's the expected value?
Approach: E[X × Y] = E[X] × E[Y] when X and Y are independent. E[single die] = 3.5. So E[product] = 3.5 × 3.5 = 12.25.
Example: You flip a coin repeatedly. You win £2 for heads and lose £1 for tails. What's the expected value per flip, and would you play?
Approach: E = 0.5(2) + 0.5(-1) = £0.50 per flip. Yes, you'd play - it's positive expected value.
Market Making and Pricing
These questions test whether you understand how market makers think about risk and inventory.
Example: I tell you a jar contains between 500 and 1500 marbles. Make me a market (bid-ask) on the number of marbles.
Approach: Your fair value estimate is 1000 (midpoint). Start with a wide spread - maybe 800 at 1200. The interviewer will trade with you. Adjust your estimate based on whether they buy or sell, and tighten your spread as you gain information. If they keep buying, your estimate should shift upward.
Example: You're market making on a stock currently at £50. A news event has a 60% chance of being positive (stock goes to £55) and a 40% chance of being negative (stock goes to £42). Where do you set your bid and ask?
Approach: Fair value = 0.6(55) + 0.4(42) = 33 + 16.8 = £49.80. Your spread should be wide enough to protect against adverse selection but narrow enough to attract flow. Something like £48.50 at £51.00 would be reasonable - you'd explain your reasoning about the asymmetric risk.
Trading Games and Simulations
The trading game is often the highlight of Optiver's assessment day. You'll typically be placed in a simulated market with other candidates, given a product to trade, and judged on your P&L, risk management, and behaviour.
Common formats include:
- Card-based games: A deck of cards represents uncertain information. You trade a "stock" whose value depends on the cards revealed. You need to update your fair value estimate as new information arrives and manage your position.
- Multi-round simulations: You trade over multiple rounds with new information each round. The game tests whether you can keep a clear head, manage inventory, and avoid getting picked off.
- Competitive market making: You and other candidates simultaneously quote bid-ask spreads. The best spreads get filled. You need to balance being competitive on spread with managing risk.
The most important thing in trading games isn't finishing with the highest P&L. Interviewers watch how you think, how you update beliefs, and whether you stay disciplined. Panicking after a loss or becoming reckless after a win are both red flags.
Coding Questions (Engineering Roles)
Software engineers face LeetCode-style problems plus systems questions:
Example: Implement an order book that supports limit orders, market orders, and cancellations. What data structures would you use for O(1) best bid/ask lookup?
Approach: Use a sorted map (or balanced BST) keyed by price level, with each level holding a queue of orders. Maintain pointers to best bid and best ask. For cancellations, use a hash map from order ID to its location in the book.
How to Prepare
Preparing for Optiver requires a different approach from standard tech or finance interviews. Here's what actually works.
Mental Maths (Start 4-6 Weeks Before)
This is non-negotiable. Practice every single day.
- Use Zetamac or similar speed arithmetic trainers. Start with the default settings and work toward completing 80+ questions in 8 minutes with over 90% accuracy.
- Drill multiplication tables up to 20 × 20 from memory.
- Practise squaring two-digit numbers: 37² = (40 - 3)² = 1600 - 240 + 9 = 1369.
- Learn to multiply by breaking numbers apart: 67 × 43 = 67 × 40 + 67 × 3 = 2680 + 201 = 2881.
- For division, build intuition for common factorisations: know that 144 = 12², 225 = 15², and so on.
Probability and Statistics (2-4 Weeks Before)
Work through classic quant interview questions focusing on expected value, conditional probability, and Bayes' theorem. Make sure you can solve problems like the Monty Hall problem, the birthday paradox, and the gambler's ruin without hesitation.
Trading Intuition (2-3 Weeks Before)
Read about how market making works. Understand bid-ask spreads, inventory risk, and adverse selection. Our quant trading strategies article covers the fundamentals. Play poker if you don't already - the skills of reading incomplete information, managing risk, and making +EV decisions under uncertainty translate directly.
Mock Interviews (1-2 Weeks Before)
Practise with friends. Have someone fire rapid mental maths questions at you. Simulate trading games with cards. The pressure of performing in front of someone else is genuinely different from solo practice.
What Optiver Looks For
Beyond raw technical ability, Optiver evaluates several traits consistently:
- Speed of thought - Can you process information and reach a conclusion quickly? This matters more at Optiver than at almost any other firm.
- Intellectual curiosity - Do you ask good questions? Do you probe deeper when something doesn't make sense?
- Composure under pressure - How do you react when you're wrong, when you're losing money in a game, or when a question is beyond your current knowledge?
- Collaborative mindset - Market making is a team sport. Optiver wants people who communicate clearly and work well with others, not lone wolves.
- Calibrated confidence - Know what you know, and be honest about what you don't. Bluffing is worse than admitting uncertainty.
Frequently Asked Questions
How hard is the Optiver maths test?
The Optiver maths test is significantly harder than it sounds. While the individual questions are basic arithmetic, the combination of speed (6 seconds per question), volume (80 questions), and escalating difficulty makes it a genuine challenge. Most candidates who haven't specifically prepared will struggle to pass. Daily practice with speed arithmetic tools for at least 3 to 4 weeks is the minimum preparation most successful candidates report.
Do I need a finance background to interview at Optiver?
No. Optiver hires from mathematics, physics, computer science, engineering, and other quantitative disciplines. Many successful traders have no formal finance education. What matters is quantitative reasoning ability, speed of thought, and intellectual curiosity. That said, understanding basic options concepts and market making principles will help in later interview rounds.
What programming languages does Optiver use?
Optiver's technology stack is primarily C++ for performance-critical trading systems, with Python used for research, data analysis, and tooling. FPGA engineers work with VHDL or Verilog. For software engineering interviews, you'll typically code in C++ or Python, though the focus is on problem-solving rather than language-specific syntax.
How long does the Optiver interview process take?
The full process typically runs 4 to 8 weeks from initial application to final offer. The online maths test result comes within a few days. Phone screens are usually scheduled within a week of passing the test. Assessment days and final rounds depend on scheduling availability, but Optiver generally moves quickly once you're in the pipeline.
Can I retake the Optiver maths test if I fail?
Optiver typically enforces a cooldown period of 6 to 12 months before you can reapply and retake the test. Use that time productively - consistent daily practice with Zetamac or similar tools will make a measurable difference. Many candidates who fail on their first attempt pass comfortably on their second after focused preparation.
How does Optiver's interview compare to Jane Street or Citadel?
All three firms are demanding, but the emphasis differs. Optiver places uniquely heavy weight on raw arithmetic speed through its maths test. Jane Street is known for longer, more open-ended probability and estimation problems with extended back-and-forth discussion. Citadel's process varies more by team but often includes heavier coding components. Our quant interview questions guide covers preparation strategies that work across all three.
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