I applied online. I interviewed at Jane Street (New York, NY) in Nov 2025
Interview
They start with three phone interview rounds, followed by a final round. The first round covers basic probability topics such as Bayes' Rule and Conditional Expectation. The second round involves more long-form applied probability problems using the same principles but with different constraints. The third round presents even more complex probability problems, still based on the same fundamental principles. The third round is significantly more difficult than the first two.
Interview questions [1]
Question 1
Short form and long form dice-roll related questions.
1st round--45 minute phone call purely technical with brainteasers. no behavorial besides brief introduction of self. i believe there are 2nd and 3rd round phone and a final superday but didn't make it past there.
multiple online interviews, technical in nature, followed by an in person in office interview which lasted an entire day and had multiple stations. focused on problem solving, probablity, game theory etc etc
I applied online. The process took 1 week. I interviewed at Jane Street (London, England) in Nov 2025
Interview
They started with a basic introductory question followed by some probability based stuff. Wasn’t too difficult but you have to ace it, they expect perfection. They cut the interview off at exactly 30 minutes, and will provide hints if you need it though it’s not a good sign if you need them.
Interview questions [1]
Question 1
You have 20 cards. 1 is black the rest are red. You keep drawing cards and get $1 for each red, but if you draw the black the game ends and you get nothing. How do you play and what’s the average payout? Now drawing the black card makes your score go negative, but you can continue drawing cards. What’s the strategy and expected payout now?