I applied online. The process took 2 weeks. I interviewed at Jane Street (London, England) in Dec 2022
Interview
If you have passed certain stage on previous year, they will let you repeat on the stage that you failed on (at least in my experience). Got onto 2nd, failed at 3rd, if you pass, you should get into onsite.
Interview questions [1]
Question 1
Probability questions, some card with ev calculations with different cases, the youtube video helps a lot.
I applied online. The process took 2 weeks. I interviewed at Jane Street (London, England) in Sept 2024
Interview
1st interview: basic probability brainteasers
2nd interview: significantly more difficult game questions one involving dice and other coins. Two players roll a dice then decide whether they pick their own, other, or withhold decision until next round. What's the optimal strategy?
Interview questions [1]
Question 1
You are playing a game where you flip a coin 5 times. You win if three heads come up in the 5 coin tosses. You lose if three tails come up in the 5 coin tosses. If you win you get £1. If you lose you lose £1. Before each flip you can choose to either double the stakes from their previous value (if you win you get £2n and if you lose you lose £2n where n is the amount you get if you win beforehand) or keep them the same. Are you willing to pay £0.50 to play this game?
Flipping coins, betting on sums, products, other interesting contracts. Some amount of being smart about formulating a market making strategy. Finally, some game theory (nash equilibrium) and excel tasks. Overall very thorough and comprehensive.
I applied online. I interviewed at Jane Street (Hong Kong) in Jun 2023
Interview
They asked entirely maths/probability questions, usually with some sort of coin toss/die roll element in the context of a game. Very friendly and patient interviewers, who will guide you through the questions.
Interview questions [1]
Question 1
We are playing a game where we roll two die. If the sum is even, you win and the game ends. If the sum is 7, I win and the game ends. If the sum is odd, we roll again. What is the probability that you win?