I applied online and a week later was set up for a phone interview with the recruiter. The one phone interview with the recruiter was straightforward with typical behavioral questions. After the interview, I was sent two links for a mental math test and logic problem-solving test. Both were pretty easy but the second was a bit more challenging than the mental math for obvious reasons. I assume I did well since I thought it was easy and sure enough was sent a request for a phone interview with someone on the team. This was the part that confused me. At first, it was all behavioral and then out of nowhere starts asking me questions related to finance. I was interviewing at HRT and Jane Street where neither of them asked me questions related to finance since my background is all tech so I just assumed Optiver would be the same. I expected only quantitative and technical questions. I pretty much bombed the finance questions but nailed the quantitative and technical questions towards the end. I ended up getting a rejection email which was kind of strange, to be honest, but I guess you win some and lose some.