I had applied on the company website. I ended up having three rounds via phone, with people in the New York, Hong Kong and London offices. Interviews were quite technical and I had answered all questions pretty well. After a few weeks I was told they would not proceed as they didn't find a good match.

Very technical based for multiple rounds (6+) focusing on calculus, probability, stats, and a few brain teasers. There is a coding test at the end, where you are given a certain time frame to submit back.