First round is a numerical and behavioural test. Numerical test is fairly challenging, mainly because of the timer, and takes a while to get used to. Spend some time practicing, and if you can find practice tests that simulate the timer elsewhere, you should practice those too. The math itself is not advanced, just table/chart reading and arithmetic based on that. Do not guess, as accuracy is important. As for the behavioural test (what they call a "cultural appraiser"), use some critical thinking and do a little bit of research on the company's culture, and the test should be easy to pass. If you pass both you should get an automated email for the second round very quickly. I got mine within the same hour.
Second round was a video "interview" on Sonru. Format: automated questions will be shown with a timer for you to read and think about your answer (1min), and then there will be a set time for you to record your answer (2min). You can choose to record it at any time before the deadline (1 week), and there's a practice interview you can take before recording the actual one. Personally I found it extremely awkward. It's supposed to simulate a real interview but it's not quite like having a real person to talk to. After this you will finally get a real HR person emailing you. I got my email for the next round about 2 weeks after I submitted my Sonru interview.
Third round was a Skype interview with 2 senior execs, which was supposed to last 1 hour according to the email. Interviewers were very knowledgeable and friendly, and happy to answer questions about current market trends and such. Unfortunately, and this is the disappointing part, I was told by the interviewers that I did not meet their requirements for the role as I do not have a degree in finance, accounting or relevant areas, or sufficient professional experience.
The listing for the trainee position that I applied to stated that UBS welcomes applicants from any field of study. I now feel like I was lied to, and that I wasted my time and energy. And why advance me so far along in the application process when you can see from my CV that I do not have the desired qualifications? They should have let me know from the point that a human read my CV that I wasn't suitable. Why even set up an interview only for the interviewers to let me down (although they were kind when they did so), and waste both my time and theirs? I took leave from my work to be able to attend the interview.