I recently helped several mentees complete the latest Optiver 2027 Online Assessment, and compared with last year's question pool, the Quant OA has changed significantly. Three brand-new assessment modules have been introduced, the overall workload has increased, and the difficulty is noticeably higher.
Most guides currently available online are based on older versions of the assessment, so this article summarizes what candidates are actually seeing in the latest Optiver OA and explains what each new section is really testing.
Overall Changes
This year's Optiver OA is split into two tracks:
- Software Engineer (SWE) — still mainly consists of coding problems plus the reaction-speed game.
- Quant — significantly redesigned with several completely new assessment modules.
The biggest change isn't that the questions became harder mathematically. Instead, Optiver now focuses much more on evaluating how quickly candidates can make good decisions under uncertainty rather than performing exact calculations.
The Six Quant OA Modules
The first three sections remain familiar to most candidates:
- Beat the Odds
- NumberLogic
- Zap-N
The three newly introduced modules are where most candidates struggle.
New Module #1 — Likelihood-list
15 Questions • 90 Seconds Each
Each problem presents historical observations and asks you to predict or rank future probabilities based on the available data.
For example, you may see several previous outcomes and need to determine which future event is most likely, ranking multiple possibilities from highest probability to lowest.
These questions rarely have one exact numerical answer. Instead, they're designed to evaluate whether you can quickly recognize statistical patterns from limited samples.
Suppose previous values are:
60 → 70 → 75 → 80 → 85
Rather than calculating complicated models, you simply recognize an upward trend and infer that the next value is more likely to continue increasing than suddenly return to 60.
This section mainly evaluates:
- Statistical intuition
- Pattern recognition
- Fast probabilistic reasoning
- Decision-making with incomplete information
Preparation Tips
- Practice identifying distributions from small samples.
- Avoid overthinking every scenario.
- Focus on recognizing dominant trends instead of searching for perfect mathematical proofs.
New Module #2 — Intervals
18 Questions • 60 Seconds Each
This module tests estimation rather than calculation.
Each question asks you to provide a lower bound and upper bound for an unknown quantity, probability, or expected value.
Typical examples include:
- Estimating probabilities from large visual grids
- Sampling without replacement
- Expected values
- Approximate ratios
One representative question asks:
A large grid contains squares, circles, and triangles. Two shapes are randomly selected without replacement. Estimate the probability of drawing exactly one square and one circle.
Since manually counting over one hundred objects isn't realistic within one minute, successful candidates estimate quantities visually, calculate an approximate probability mentally, and submit a reasonable interval.
Another simpler example:
Two people each roll one fair six-sided die. What is the probability that your friend's roll is higher than yours?
There are 36 equally likely outcomes, with 15 favorable cases.
15 ÷ 36 ≈ 42%.
Instead of entering exactly 41.67%, you might confidently submit:
Lower Bound: 40 Upper Bound: 43
The emphasis is on being approximately correct—not perfectly precise.
Preparation Tips
- Practice mental estimation every day.
- Improve arithmetic speed.
- Learn to judge the correct order of magnitude quickly.
- Accept "good enough" estimates rather than chasing exact answers.
New Module #3 — Orderbooks
20 Questions • 8 Minutes Total
This is arguably the most interesting addition because it closely resembles actual trading work at Optiver.
Each question presents an order book containing bids and asks. Your objective is to identify profitable trades or inventory-clearing opportunities as quickly as possible.
With only about 24 seconds per question, candidates don't have time for deep analysis.
The key skill is immediately spotting situations such as:
- Crossed markets
- Obvious arbitrage opportunities
- Safe inventory reductions
- Profitable execution sequences
This section primarily evaluates:
- Market intuition
- Reaction speed
- Understanding of bid/ask mechanics
- Basic trading logic
Preparation Tips
- Understand how order books work.
- Learn bid, ask, spread, and market making fundamentals.
- Train yourself to scan for obvious pricing opportunities instead of overanalyzing every card.
Question Volume and Passing Strategy
These three new modules alone contain:
- Likelihood-list: 15 questions
- Intervals: 18 questions
- Orderbooks: 20 questions
That's a total of 53 new questions, all completed under significant time pressure.
Most candidates report having virtually no time to review answers. Success depends on making strong first-pass decisions.
Although Optiver does not publish official scoring criteria, candidate feedback suggests that the assessment rewards reasonable judgment rather than perfect precision.
A sensible probability interval, a safe arbitrage decision, or a statistically reasonable prediction is often more valuable than spending extra time searching for an exact solution.
How the 2027 OA Differs from Previous Years
Earlier versions of the Quant OA rewarded extensive practice with known question patterns.
The 2027 assessment shifts toward evaluating practical thinking.
Instead of asking whether you've memorized certain question types, Optiver now wants to know whether you can make sound decisions when:
- information is incomplete,
- time is extremely limited, and
- exact answers are impossible.
Viewed from this perspective:
- Likelihood-list measures decision-making under uncertainty.
- Intervals measures estimation ability.
- Orderbooks measures market intuition.
Understanding these underlying skills is far more valuable than memorizing individual questions.
Preparation Advice
- Focus on mastering the reasoning behind each module instead of blindly grinding question banks.
- Build strong statistical intuition for Likelihood-list.
- Practice mental math and estimation for Intervals.
- Learn order book mechanics and market making concepts before attempting Orderbooks.
- Simulate the real time pressure during practice sessions.
Final Thoughts
The latest Optiver Quant OA is not necessarily more mathematically difficult, but it is considerably more demanding in terms of speed, judgment, and decision-making under uncertainty.
The assessment closely mirrors the mindset required in quantitative trading: making fast, reliable decisions without having perfect information.
If you prepare with that objective in mind rather than simply memorizing question types, you'll be much better positioned for success.
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