Python take-home challenge which involved some statistical modeling. After this, second round with a trader/developer. Overall, firm took about 2-3 weeks to get back to me regarding anything, extremely slow and does not seem to value your time whatsoever. Also, got rejected with no explanation - got all technical questions right in second round interview and seemed to have decent conversation with interviewer re: experiences, but didn't hear back for 2.5 weeks and then got a boilerplate rejection email.