I attended the in-house day which I suggest anyone to attend as it gives plenty of insights about the company and the business model. There is a trading simulation in the end which I found interesting and challenging. Also a chance to get to know the HR who is very kind and approchable and to meet some junior traders. First step of the interview process is a mental math test, 75 questions in ten minutes. Then a sequence/pattern recognition test that lasts an hour aproximately. I passed both tests. In the end the tests are challenging, but if you prepare a bit before they are definitely manageble. After that an interview with the HR lady and a senior trader, mainly on motivation. Second step is an arbitrage case study followed by a discussion with two traders. The case study is quite challenging, but manageble as well. It can't be prepared as it is quite unique I would say. I did not perform at best, in the end I answered all the questions of the traders, but it took me some time. I have been told later that they really value speed and fast thinking in giving the answers. The traders also try to put pressure on you and challenge everything you say, to simulate the stress in the trading floor. All in all it was a great experience, company responds super fast, interview process is very transparent and people are really nice. Also, their office in Amsterdam is spectacular.

First was a mental maths test of roughly same level as Optiver 80 in 8. Then had a 1-1 interview with HR, did not pass as had not researched company well enough.