I applied online. The process took 4 weeks. I interviewed at Optiver in Jan 2016
Interview
Behavioral and technical phone interviews, followed by an in person interview in their office in chicago. Everyone was super friendly, asked tough questions. Seemed to be interested in how you think and particularly how quick you are
Interview questions [1]
Question 1
Lets play a game where we roll a dice and you get a dollar amount equal to the dice roll. If you don't like your result, you can re-roll the dice once. How much would you pay to play this game?
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.