Chicago Trading Company Interview Guide: OA & Questions

The short answer

Chicago Trading Company (CTC) recruits through an application, a role-specific aptitude or coding assessment, technical and behavioural interviews, and sometimes a final team visit. For Summer 2027 quantitative trading candidates, the early test has used the 50-question, 15-minute CCAT; software engineering applicants have also encountered a separate Codility coding assessment.

Trading interviews emphasise probability, statistics, mental arithmetic and market-making decisions. Software engineering and quantitative research applicants face different technical work, so prepare for your actual role rather than treating every CTC assessment as a trading test.

How the CTC interview process works

CTC's published early-careers process has four broad steps: apply, complete an assessment if invited, meet the team through technical and behavioural interviews, and potentially visit or meet more of the firm. The exact sequence becomes more specific once you distinguish Quant Trading, Software Engineering and Quantitative Research.

Application. Select the CTC role matching your background. For the Chicago Summer 2027 Quant Trading Internship, the posting allows one application per position and permits separate applications for trading and engineering roles.
Assessment. Trading applicants have encountered a fast cognitive-aptitude test. Software engineering applicants have encountered an aptitude and work-style assessment followed by a separate timed coding test.
Technical and behavioural interviews. Trading applicants solve probability and market-making problems; software applicants explain and write code; researchers defend project choices and statistical methods. CTC also evaluates collaboration and judgement.
Final conversations. The last stage can be a virtual behavioural interview for an intern or a longer set of interviews for a graduate role. Some finalists are invited to meet the team or visit the office.

For the 2027 Chicago trading-intern cohort, a completed aptitude assessment has been followed by a trader-led technical round and a virtual behavioural final. In the 2027 graduate Quant Trading Associate (QTA) track, a 90-minute behavioural stage has also been used before a further final-round interview.

CTC hires people into different jobs and at different career stages. A senior options trader's interview can centre on past positions, pricing and risk rather than the student aptitude sequence.

CTC online assessment: the CCAT and aptitude test

The Summer 2027 Quant Trading Internship screening has used the Criteria Cognitive Aptitude Test (CCAT), a speeded reasoning assessment rather than a probability interview. Candidates in August 2026 described a 50-question test lasting 15 minutes, matching the format published by the assessment provider.

The CCAT mixes verbal reasoning, mathematical and logical reasoning, and spatial patterns. Criteria prohibits calculators, and its scoring counts correct answers rather than requiring every question to be attempted.

CCAT component	What you actually do	Useful preparation
Numerical and logical	Compute percentages, ratios and short word problems; identify number patterns.	Practise mental arithmetic and fast elimination of implausible options.
Verbal	Choose synonyms, interpret statements and solve short language-based reasoning items.	Do mixed vocabulary and reading-inference questions against a clock.
Spatial	Identify a missing shape or the next step in a visual pattern.	Practise transformations, rotations and shape-sequence questions.

Fifteen minutes for 50 questions averages just 18 seconds per item, although you should not spend exactly 18 seconds on every question. Criteria says fewer than 1% of test-takers answer all 50, and there is no penalty for incorrect answers.

Start with a timed mixed set, practise quickly skipping questions that are consuming the clock, and review which categories cost you the most time. Read the instructions before your actual attempt and follow the permitted-resource rules in your invitation.

Important distinction

CCAT is a general cognitive test, not a timed version of CTC's probability interview. The firm's published recruiting outline allows different assessments by role, and a separate software coding test is discussed below.

A quick original aptitude example

A price rises by 20% and then falls by 15%. If it began at $80, what is its final value?

Show the calculation

Multiply the factors rather than subtracting the percentages: 80 × 1.20 × 0.85 = 81.60. The final price is $81.60, a 2% increase from the starting price.

This exercise is original practice, not a confirmed CTC test item. Its purpose is to train short, accurate computations without reaching for a calculator.

CTC Software Engineering online assessment and Codility

The Summer 2027 Software Engineering Internship screening has included an aptitude and work-style assessment followed by a separate Codility coding test. For that 2027 internship track, applicants in July 2026 completed three Codility programming problems in a three-hour window; a Summer 2026 candidate had earlier taken three problems in 170 minutes.

The coding problems reward accurate simulations and careful handling of state, not just recognising a named algorithm. A 2026 Associate Engineer assessment included tasks involving bank balances, digit-pattern generation and stack operations, while current internship applicants have also described three-question tests.

What to prepare for the Codility stage

Stateful simulations: process events in the correct order, keep balances or inventory consistent, and detect the first violation of a constraint.
Arrays, strings and stacks: parse an operation sequence, track intermediate values and handle malformed or boundary inputs as required by the specification.
Complexity and hidden cases: examine input limits, design custom tests, and avoid a slow nested loop where a running sum or hash map is sufficient.

For a realistic practice benchmark, solve three original coding problems in three hours and reserve the last 20 minutes for hidden-case-style checks. This is a preparation target based on a documented historical format, not a promise that every engineering applicant receives the same test.

What happens after the coding OA?

Live engineering interviews can involve implementing a problem while sharing a browser-based coding environment. A September 2026 internship interview included two stock-profit calculation problems in a one-hour Zoom session with an interviewer observing the code.

CTC's Summer 2027 software application also asks which programming language you prefer for technical interviews so the team can match you with a suitable interviewer. Choose the language in which you can explain your data structures and test behaviour most clearly.

CTC Quant Trading technical interview questions

The first trading interview moves from aptitude speed into mathematical reasoning with an interviewer. CTC's recent Quant Trading Intern and Quant Trading Associate interviews have included probability brainteasers, statistics, mental arithmetic, market-making problems and discussion of a candidate's CV.

A 2025 internship interview for an August cohort ran for 75 minutes and covered probability, statistics and data analysis. Its questions included transforming exponential-looking data before linear regression, explaining regression assumptions, correlation and combinatorics.

Other 2026 trading interviews have tested rapid double-digit multiplication, prices in a market-making game and the ability to remember earlier quotes. You need to explain a chain of reasoning clearly while keeping enough attention free to respond when the problem changes.

Mathematics worth knowing before the call

Conditional probability: update a probability after receiving a signal, distinguishing P(A | B) from P(B | A).
Expected value and counting: price a discrete payoff, enumerate outcomes without double-counting, and decide when a bet has positive expectation.
Statistics and regression: understand covariance, correlation, independence, transformations and what a residual plot reveals about a model.
Mental arithmetic: calculate percentages, squares near round numbers and two-digit products aloud without long pauses.

For example, 51 × 51 = (50 + 1)² = 2601 is the kind of mental-maths calculation that has appeared in an older CTC quantitative trading analyst interview. The difficulty comes from handling several small problems accurately while continuing to explain your approach.

Before an interview, solve a handful of conditional-probability and regression questions without notes, then explain why each answer is reasonable. Add a timed oral exercise in which a friend interrupts with new information halfway through the problem.

Market-making games and trading decisions

CTC trading interviews have used market-making games in which you quote a price and react to new information. An October 2026 Quantitative Trader Analyst Intern interview specifically involved mental maths, probability, market making and data analysis, with questions later revisiting quotes made during the game.

Start each round by stating the expected value of the payoff. Then choose a bid and ask around that value, explain how uncertainty affects your spread, and update both quotes when your information or position changes.

How to handle a changing market

Value the contract. Identify outcomes, probabilities and payoffs; calculate a fair value before giving a tradable quote.
Quote both sides. Set a bid below your fair value and an ask above it, with a spread that reflects the uncertainty and the game's rules.
Track inventory. Record whether you bought or sold contracts and at which prices. If you sell too many, another sale increases your short exposure.
React and review. Incorporate new information, explain the new valuation, and remember previous trades so you can reconcile your final position and expected P&L.

Run a five-round mock game with changing probabilities and record each bid, ask, fill and inventory update. That is an EverythingQuant practice exercise, not a claim about how many rounds CTC's actual game contains.

Behavioural interviews, final rounds and the superday

Behavioural interviews carry meaningful weight at CTC, including for technical candidates. The firm explicitly looks for curiosity, ownership, collaboration, careful reasoning and openness to feedback, and recent trading applicants have faced dedicated behavioural sessions rather than only a few questions at the end of a technical call.

The 2027 graduate QTA process has included a 90-minute behavioural round with two interviewers before a further superday. In the Summer 2027 Chicago trading-intern process, a virtual behavioural interview has instead served as the named final round after the technical screen.

Prepare clear examples of a difficult team disagreement, a mistake you owned and corrected, and a decision you made under uncertain information. Expect interviewers to press for what you personally did, how you changed your approach and what happened afterward.

Experienced trader interviews can also go deep into previous work, strategy decisions, options knowledge and disagreements with colleagues. Treat those conversations as an opportunity to reconstruct actual decisions rather than to recite a polished script.

How CTC interviews differ by role

CTC's roles share an emphasis on quantitative problem-solving, but they assess different work. The current firm role descriptions and the distinct interview experiences point to three useful preparation tracks.

Quant Trading Intern and Quant Trading Associate

The intern and graduate QTA tracks reward probability fluency, statistical reasoning, fast calculations, market quoting and practical judgement. CTC describes the QTA role as involving trade execution, strategy formulation, backtesting, data analysis and derivatives pricing.

Choose exercises where you need to quote an expected value, defend your spread and explain a trade after the odds change. Practise answering a statistics question about correlation or transforming nonlinear data without reading from a formula sheet.

Software Engineering Intern and Associate Engineer

Programming interviews focus on turning specifications into correct code and explaining why the solution works. CTC's recent coding tasks have involved stacks, event processing, balance constraints and financial calculations rather than only standard textbook patterns.

Write small tests for empty input, repeated operations, negative balances and large sequences, then explain time and space complexity. For more experienced C++ or systems roles, extend preparation to performance, concurrency and memory behaviour relevant to the job description.

Quantitative Researcher and systematic research roles

A 2026 PhD Quantitative Researcher process has included a research-focused first screen, a statistics test, a pandas and time-series data exercise lasting a couple of hours, and behavioural interviews. Other early research screens have involved detailed questions about a machine-learning project and the candidate's modelling choices.

Practise explaining your strongest research project from dataset construction through estimation, validation and failure analysis. Be ready to manipulate a time-indexed dataset, discuss leakage, explain confidence intervals and defend why a statistical result would survive a different market regime.

CTC-style interview practice questions with solutions

The following problems are original EverythingQuant exercises selected to match skills relevant to CTC's trading, research and engineering interviews. They are not presented as leaked, repeated or guaranteed CTC questions.

1. Trading and probability: reprice a binary contract

A contract pays $12 if event A happens and $0 otherwise. Before any signal, the probability of A is 30%; a positive signal occurs 75% of the time when A happens and 25% of the time when it does not.

After a positive signal, what is the fair price of the contract? If you sell ten contracts at an ask of $7.10, what is your expected profit based on that updated fair value?

Show the worked solution

Use Bayes' rule with the joint probabilities: P(A and positive) = 0.30 × 0.75 = 0.225 and P(not A and positive) = 0.70 × 0.25 = 0.175. A positive signal therefore occurs with probability 0.225 + 0.175 = 0.40.

The updated event probability is 0.225 / 0.40 = 0.5625, so the fair contract value is 12 × 0.5625 = $6.75. This is higher than the original fair value of 12 × 0.30 = $3.60.

Selling at $7.10 gives an expected edge of $7.10 − $6.75 = $0.35 per contract, or $3.50 across ten contracts before costs and additional risk. You are short ten contracts, so you should still track inventory and reprice after further information.

2. Statistics: recognise a nonlinear relationship

You plot a positive response variable against time and the curve grows approximately exponentially. Someone proposes fitting a straight-line regression to the original values.

What transformation should you consider, and which assumptions would you examine before trusting the fitted relationship?

Show the worked solution

If the model has the form Y = a × exp(bX) × error with positive multiplicative error, take a logarithm of the response. Then log(Y) = log(a) + bX + log(error), which is linear in X.

Check whether the transformed residuals exhibit systematic curvature, changing spread or dependence across observations. Also check influential points and whether the data are genuinely positive, since taking logarithms of zero or negative values is not defined in the real numbers.

A good answer notes that a strong fit on the log scale does not automatically imply an unbiased prediction of the arithmetic mean of Y. Converting predictions back to the original scale can require an adjustment for the residual distribution.

3. Software Engineering: minimum cash buffer

A trading account receives a sequence of daily signed cash changes. Write a function returning the smallest non-negative initial balance that keeps the account balance at or above zero after every change.

For [-7, 4, -5, 9], the required starting buffer is 8. Explain how your solution handles an empty sequence and why it runs efficiently.

Show a Python solution

Track the running sum and its lowest prefix value. The opening balance only needs to offset the greatest deficit reached by any prefix.

def minimum_buffer(changes):
    balance_change = 0
    lowest_prefix = 0

    for change in changes:
        balance_change += change
        lowest_prefix = min(lowest_prefix, balance_change)

    return -lowest_prefix


assert minimum_buffer([-7, 4, -5, 9]) == 8
assert minimum_buffer([4, -10, 3]) == 6
assert minimum_buffer([3, 2, 1]) == 0
assert minimum_buffer([]) == 0

The example prefix sums are -7, -3, -8, 1, making the minimum -8. The algorithm uses O(n) time for n changes and O(1) auxiliary space.

Test a single loss, all-positive changes, an empty input and a sequence that returns to zero. If the interview introduces multiple accounts or transfers, be ready to explain what state must be tracked separately.

How to prepare for a Chicago Trading Company interview

Start with the next stage you have actually been invited to take. A high CCAT score does not replace the probability and trading discussion, and a trader's mental-maths preparation does not replace Codility practice for a software engineer.

For a trading aptitude invitation: complete two or three 15-minute mixed CCAT-style drills, without a calculator, and review your slowest categories. Prioritise question selection and correct answers over trying to finish every item.
For a trading technical call: solve probability, Bayes, combinatorics and basic statistics problems aloud. Add daily mental maths and a mock market-making game with a running record of quotes and positions.
For a software Codility invitation: solve simulations, stack problems and array or string tasks in a timed editor. Practise creating tests beyond the sample cases and stating complexity before submitting.
For a research interview: rehearse a ten-minute explanation of one project, then invite detailed questions on modelling assumptions, data leakage, out-of-sample validation and the code needed to reproduce results.
For the behavioural stage: prepare specific stories about disagreement, feedback, ownership and working under uncertainty. State your own decisions and what changed because of them.

EverythingQuant already has a Chicago Trading Company interview question bank covering probability, mental maths, optimisation and trading games. Work through it as representative preparation, not as a list of guaranteed past interview questions.

To strengthen the foundations, use the Probability for Quants course or the coding interview questions. If you need a schedule across assessments and interviews, build a personalised preparation roadmap.

Chicago Trading Company interview FAQs

Is the CTC online assessment automatic?

Summer 2027 trading applicants received aptitude invitations as soon as one or two days after applying, but CTC has not published a rule that every application receives an automatic test. A quick assessment invitation does not by itself establish that the entire resume review has been completed.

Is the CTC OA a CCAT or a Codility test?

The 2027 trading-intern aptitude screen has used CCAT-style cognitive questions, while software engineering candidates have also taken a separate Codility programming assessment. Prepare for the actual assessment named in your invitation instead of importing an engineering test format into a trading application.

Do I have to answer all 50 CCAT questions?

No. Criteria says fewer than 1% of test-takers finish all 50 and that the CCAT has no penalty for wrong answers, so use the clock strategically and avoid spending too long on one item.

What CCAT or Codility score passes the CTC assessment?

CTC does not publish a verified universal passing score for either assessment. The CCAT produces a raw score and percentile, while programming assessments evaluate solutions against tests; focus on accuracy rather than an unverified cutoff circulating online.

Does the CTC internship always include a superday?

The 2027 Chicago trading-intern process has used a virtual behavioural final after the technical screen. Graduate QTA recruitment has also included a further superday, so the intern and graduate endings should not be treated as identical.

Do I need to know options or have a finance degree?

CTC explicitly says prior finance experience is not required for its trading internship, and its early-career training covers options fundamentals and market making. For a technical interview, learn payoffs, expected value and the intuition behind a two-sided quote rather than relying on a finance degree.

What is the CTC Options Theory Intensive?

It is a separate 2027 QTA entry route involving four days of learning in Chicago and an assessment day, with strong performers eligible for a QTA final-round interview. It should not be confused with the standard remote online aptitude test.

How long does it take to hear back after a CTC assessment?

In the Summer 2027 trading-intern cycle, one applicant moved to a technical interview roughly a month after the OA; other applicants received an aptitude invitation within days of applying. These are different stages of the process, and CTC does not publish a fixed interview-response deadline.

Sources and editorial notes

This independent guide draws on CTC's published recruiting information, the CCAT provider's test guide, and dated first-hand accounts of the 2025–2026 recruiting cycles. Role- and cohort-specific interview details are historical observations, while the worked problems and timed drills above are original EverythingQuant practice.

Chicago Trading Company (CTC) Interview Guide

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