First round interview involved a surprise essay: choose one topic to write about for a half hour from a selection. Followed by a series of motivational questions and mathematical brainteasers (many available online, the most comprehensive selection I found were under "Jane Street" interviews on Glassdoor!) Second round involved preparing and presenting a financial model from a given case study (provided a week prior to the interview). Further clarifications of details related to the model and mathematical brainteasers. This was followed by an informal meet with current analysts. Both interviews were 1:2.

First, you are interviewed by a HR person and a member of the relevant team, in my case the financial modelling team. They ask you a few mathematical puzzles and questions about your CV. If successful, they invite you for another interview, this time, they will send you the details of a prject for you to perpare a presentation, with cash-flows and analysis for a client recommendation. Expect to be question on every decision you make on the way you analyse the different secenarios and get technical. This interview is conducted by a sr manager and a technical member of the team. At the end there's an informal drinks ocassion.