It was not difficult. After finishing its OA, there was only one round interview mainly about your resume. Some interviewers may ask some brainteaser questions but most are standard ones.

It was pretty harsh as the questions are deep. I was asked about data structure (hash table), asset allocation strategies, portfolio optimization, etc, programming experience. There are also questions like given some conditions, how would you evaluate whether you have put proper weights on your assets in your portfolio.