I had a 30-minute on campus interview with one of Blackrock's VP of Sales. This preliminary interview was mostly behavioural in nature. Nothing out of the ordinary - questions were focussed on: your academic background, extra-curricular involvement, why you're interested in working at BlackRock, your strengths/weaknesses. After this initial interview, I was invited to BlackRock's "Superday" at the local office. I had an interview with four of their employees (all of various tenures/seniority levels within the firm) for between 20-30 minutes per interviewer. Each of these four interviews varied quite a bit. In general, there was still mostly behaviourial with the occasional technical question thrown in. This is probably because the firm evaluates your technical ability with a short test at the end of your interview. The test was a little ambiguous and I was not particularly clear on what was asked. The individual who assigned the technical test essentially told me to look for errors in the tables of data and identify them - that was the extent of the instruction I received. In hindsight, I should have probably spent 30-60 seconds asking the interviewer for some additional details. In general, you should always do this for any of your interviews anyway... the worst that can happen is they'll say, "No". But if they do provide you with some additional details it could make the difference between knowing what is asked of you and confidently tackling the technical assessment or just sitting there feeling somewhat clueless about what it is that you're trying to look for (like I did).