I applied through an employee referral. The process took 4 weeks. I interviewed at Optiver in Sept 2021
Interview
Had online assessment, then phone screener with recruiter, and finally a final round
Phone screener was behavioral based, no technicals
Final round was 2 technical parts and a behavioral with DS manager
Interview questions [1]
Question 1
Final round consisted of linear model analysis and a sports betting game
First round is HR interview, all BQs. Second is Tech round, gave me a hard level Leetcode problem. Third round is a case study, I forget the detail but it is a really complicated problem, a lot of data details need to be noticed. My programming language is Python.
HR Phone Interview: All BQs
Online Assessment: HackerRank (prolly some python Qs just forgot)
On-Site Tech Interview: Probabilities and Statistics
Final BQ Interview
The whole process took about a month, casual interview vibe
Got an online coding test invitation immediately after submitting an application. It took three hours, but I didn't proceed to the next round. I don't remember all of the questions, but one was coding up a trader analyzer