I applied online. The process took 1 week. I interviewed at Optiver (Chicago, IL) in Oct 2015
Interview
8 min mental math test pre screen. Need 55/80 to pass.
Initial phone screen with a trader - entirely behavioral. Second round phone interview with someone from education department, half behavioral, half technical.
Onsite: they make you do the 8 minute prescreen again to make sure you didn't cheat. I found the onsite pre-secreen easier than the one I did at home. Followed by 30 min sequences test.
Then initial behavioral interview with hr, followed by technical from two traders. Behavioral from two more traders. Quick chat with manager of Chicago office.
They're interested in how you think or explain your answers.
Interview questions [1]
Question 1
Walk me through your resume? Why do you want to work here? What are 5 qualities that are most important to being a trader? If you have other offers, how will you choose between firms?
spent about 1.5 months pretty much purely dedicated to preparing for interviews for all the pre-penultimate programs (Optiver, IMC, JS, SIG, Citadel, etc). I used these resources:
Green book (Really good starter but I got bored of it after a few weeks)
EverythingQuant (Went through literally every single interview prep question, went through the interview guides, and completed the probability course just to make sure I covered all bases)
Briefly read through this guide
Watched coding Jesus in my spare time (not sure if this helped directly lmao but he’s a great creator and very informative)
Mental math test, beat the odds, online puzzle like games etc online, brain teasers during physical interview and a behavioral interview where they want to assess how competitive and assertive you are.
OA was weird and hard. there was only three sections (i think) this year compared to 5 last year. questions are weird and I don't know how they can judge your ability base on that.