I recently went through a virtual onsite and had 2 rounds of interviews, all coding questions were Bloomberg LC tagged and I was asked one System design question that went something like, design a system that pulls in stock information from multiple stock exchanges and a client needs stock prices for a certain stock from all these exchanges and also top K stocks throughout the day. I proposed a pub/sub system but the interviewer didn't seem very happy. I'd appreciate your ideas on how you would have designed such a system. Thanks!