Interactive Brokers Software Engineer (Mid level) interview questions

I applied online and received take home assessment. Once you qualify the assessment you can schedule date for pair programming. You get introduced to the team and there is 50 minutes allocated to complete the challenge. They walk through the solutions and asked questions about your approach. Few questions on multi threading and Singleton. The team has been very helpful and correct any mistakes that I made.

Head hunter arranged this interview for me. First I had to complete a coding test in 2 hr time. Questions were based on C++, Java, Logic Problems. After a week I was contacted for a Personality index test, which i cleared. Later, I had 2 interviews with Hiring Managers. The first interview was mostly behavioral and on some understanding of Finance. The second interview was mostly the same behavioral stuff but by a technical manager. He asked me what type of testing units I knew, whether I knew SQL. 2 weeks later they replied with a negative. However, the next step was to fly in and have an interview day.