Guide · SIG
SIG (Susquehanna) interview questions and how to prepare
26 problems · 7 min read · updated 2026-09-07
Susquehanna built its trading culture on poker, and its interviews show it. The questions are framed as bets: what are the odds, how much would you wager, what does the other player’s action tell you? A candidate who can compute an expectation is table stakes; SIG is looking for the one who then asks whether the bet is worth taking at all, and at what size.
This guide is organised the way SIG thinks — edge, then odds, then decision — and every question links to a worked solution and a review queue.
Betting, odds and edge
Convert odds to probabilities instantly, spot the bookmaker’s margin, recognise a Dutch book, and know why a doubling "system" makes no money. These are asked early and they set the tone.
A betting market quotes decimal odds of 4.0 on an outcome (total payout per $1 staked). Ignoring any bookmaker margin, what probability of the outcome does this quote imply, in percent?
Answer: 25 · Worked solution →
A sportsbook quotes both sides of an evenly-matched game at American odds of −110 (stake 100). Implied probability of a −110 quote is 110/210. By how much do the two implied probabilities exceed 100%? Give the overround in percent.
Answer: 4.76 · Worked solution →
Bookmaker A offers decimal odds of 2.2 on team X winning; bookmaker B offers decimal odds of 2.2 on team X not winning (decimal odds = total payout per 100, split so that your payout is the same either way. What is your guaranteed profit, in dollars?
Answer: 10 · Worked solution →
European roulette has 37 pockets (0–36). A $1 bet on a single number pays 35-to-1. What is the house edge — the casino’s expected profit per dollar staked — in percent?
Answer: 2.7 · Worked solution →
On a fair even-money coin flip you play the classic martingale: bet $1, and after every loss double the stake until the first win, then stop. Ignoring any table or bankroll limit, how many dollars does every completed run of this system win?
Answer: 1 · Worked solution →
An interviewer asks you to make a market on the sum of two fair six-sided dice. Before you quote a bid and an ask, you need the fair value. What is it?
Answer: 7 · Worked solution →
Probability that turns into a bet
Standard probability questions, each followed by "would you bet on that?". Expected minimum of two dice, the top two cards being aces, the Tuesday boy, hitting a pattern — compute, then price.
You roll a fair die 4 times. What is the probability of getting at least one 6? (Round to 3 decimals.)
Answer: 0.518 · Worked solution →
A standard 52-card deck is shuffled. What is the probability the top two cards are both aces? (Enter as a fraction or decimal.)
Answer: 1/221 · Worked solution →
Two fair dice are rolled. What is the expected value of the smaller of the two (ties count as that value)?
Answer: 91/36 · Worked solution →
A family has two children. You learn that at least one of them is a boy born on a Tuesday (assume boys and girls, and all birth days, are equally likely and independent). What is the probability that both children are boys?
Answer: 13/27 · Worked solution →
What is the expected number of fair-coin flips to first see the pattern H-T-H?
Answer: 10 · Worked solution →
You start with 1 on a fair coin each round, stopping when you reach 100. What is the probability you reach $100 before going broke?
Answer: 0.3 · Worked solution →
You start with 1 on a fair coin each round, stopping when you reach 100. What is the expected number of rounds until you stop?
Answer: 2100 · Worked solution →
Sizing and decision under uncertainty
Kelly with real odds, the adverse-selection question that decides whether you understand where a market maker’s edge comes from, and games whose value depends on when you stop. SIG asks these as conversations about what you would actually do.
A repeatable bet wins with probability 40%. A win pays 2-to-1 (win 1 staked); a loss costs the stake. What fraction of your bankroll should you stake per bet to maximise long-run growth (the Kelly fraction), in percent?
Answer: 10 · Worked solution →
You can repeatedly make an even-money bet (win or lose the amount staked) that you win with probability 60%. What fraction of your bankroll should you bet each time to maximize long-run growth?
Answer: 0.2 · Worked solution →
A binary asset settles at 100 or 0, each with probability 1/2. Of the traders who arrive, 20% are informed (they know the outcome and trade in its direction) and 80% are noise traders who buy or sell with probability 1/2 each. A single trader arrives and buys from you at your ask. To break even in expectation against this flow, what is the lowest ask you can quote?
Answer: 60 · Worked solution →
You roll a fair die and are paid its face value in dollars, but you may re-roll up to two times, keeping only the final roll. Playing optimally, what is this game worth?
Answer: 4.67 · Worked solution →
Cards from a shuffled standard 52-card deck are revealed one at a time. Your running total gains 1 for every black card. You may stop whenever you like and collect the running total (you may also stop immediately at $0). Playing optimally, what is this game worth?
Answer: 2.62 · Worked solution →
Options intuition
SIG is one of the largest options market makers; expect sign-of-Greek questions and simple strategy valuations, asked with the same "would you buy it here?" framing.
For a long vanilla option with no carry, is theta (sensitivity to the passage of time) typically positive or negative, and why?
You buy a straddle struck at 100 for a total premium (call + put) of $8. What is the upper breakeven stock price at expiry?
Answer: 108 · Worked solution →
You buy an at-the-money straddle (one call and one put, same strike and expiry) on a non-dividend stock. Roughly what is the net delta of the position?
Answer: 0 · Worked solution →
Roughly what is the delta of an at-the-money European call on a non-dividend stock with short time to expiry?
Answer: 0.5 · Worked solution →
As an at-the-money option approaches expiry, what happens to its gamma — and why?
Math and games
Occasional calculus with a maximisation flavour and combinatorial games — the Nim family — where the winning strategy is an invariant.
What value of x > 0 maximizes ? (Enter a decimal.)
Answer: 2.71828 · Worked solution →
Five rational pirates split 100 gold coins. The most senior proposes a split; if at least half (including the proposer) approve, it passes — otherwise he is thrown overboard and the next-senior proposes. Pirates prioritise survival, then gold, then bloodthirst. How many coins does the most senior pirate keep?
Answer: 98 · Worked solution →
How to approach these in the interview
Price everything. After computing a probability, convert it to odds and say whether you would bet at the odds offered. SIG interviewers are listening for that reflex more than for the number.
Talk about the other player. In any game question, ask what the counterparty’s action reveals. That is the poker instinct SIG hires for, and it is the same reasoning as adverse selection in market making.
Be calibrated, not confident. SIG will offer bets at bad odds to see if you take them. Declining a bet with a reason is a strong answer; taking every bet is a weak one.
Know your Kelly. Full Kelly, half Kelly, and why desks run below it. It comes up in nearly every SIG loop in some form.
Frequently asked
Why does SIG use poker in interviews?
Susquehanna trains its traders through poker because it teaches decision making with incomplete information, bet sizing by edge, and reading what an opponent’s action reveals — the same skills as market making. Interview questions are framed as bets for the same reason.
Do I need to know how to play poker for the SIG interview?
Not the game itself, but the concepts: expected value of a bet, pot odds versus win probability, and updating on an opponent’s action. All of the questions above test those concepts without requiring poker knowledge.
What is the SIG assistant trader interview like?
Several rounds of probability, betting and market-making questions with traders, usually including a game or two, plus fit and motivation questions. Quant research roles add statistics and a coding round.
How does SIG compare to Optiver and Jane Street?
SIG is the most decision-oriented of the three — it cares about how you size and whether you take a bet. Optiver is fastest and most arithmetic-heavy; Jane Street goes deepest on follow-ups.
Practise these with answer checking and spaced review
All 188 problems, full worked solutions, and a review queue that brings each one back before you forget it. Free.
Get started freeRelated guides