Interview process was very long and grueling. Interviewed on two occasions with senior quants. The second really tested my knowledge based. Was extremely difficult interview and his personality was a bit standoffish but his comments on his interview style were fair. Took a mental math and logic test and then was moved into the final stage/ CEO interview. After 4 weeks of rescheduling the HR person told me the CEO closed the position. Entire process moved extremely slow and took over months.