I applied online. The process took 4 weeks. I interviewed at Optiver (Chicago, IL) in Nov 2022
Interview
After application you first got an online assessment (2-3 coding questions I believe?), and after you pass that you'll have two technical interviews back to back, each for 45 min. If you pass that then there will be a more "talking" non-technical interview round.
Interview questions [1]
Question 1
Two questions about the normal distribution and their moments, and two brain-teaser kind of questions.
Online assessment including Hackerrank. After 2 months I received an invitation for a HR round (the classic stuff), then a technical round, take home assignment then final round split into technical then HR.
Online assessment with 30 timed multiple-choice questions. You have a minute and half for each question, Once the timer runs out you can't go back to that question. A big portion of the problems involve random walk. Some questions require an exact solution, and some are estimates.
A long and exhausting OT of a few sections. Then some interviews on standard green book questions. In between one HR interview. Final round on a take-home ML project. Overall nice experience and HR provides feedback throughout all interviews.