Just cleared the Morgan Stanley senior SWE loop for a VP-level role in their Technology division, NYC. The system design round was a full 60 minutes and nothing like what I prepped for at FAANG.
First thing to know: they care a lot about financial systems constraints. Not just "design Twitter" style. My prompt was essentially: design a high-throughput order execution system that can handle 100k+ events per second with strict consistency guarantees. They were specifically probing whether you understood why eventual consistency is a non-starter for anything touching trade settlement.
What they tested: Low-latency vs. throughput tradeoffs in a financial context Exactly-once message delivery (Kafka, idempotency, deduplication keys) How you'd handle a downstream failure without dropping an order Database choice: why not Postgres at that scale, what you'd use instead (they seemed happy with ClickHouse + Redis combo for different layers) Audit logging requirements. This came up unprompted and they nodded visibly when I mentioned regulatory retention requirements.
The interviewer was a principal engineer. He would not just let me wave my hands. When I said "we'd shard the database," he immediately asked how I'd handle cross-shard transactions for multi-leg trades. I didn't have a perfect answer but I talked through the tradeoffs openly and that seemed fine.
Time management matters here. I spent too long on the initial design and rushed the deep dive. They didn't cut me off but I could tell we were behind. Aim to have your high-level diagram done by minute 15 so you have 40 minutes to go deep.
Level they're interviewing for affects expectations a lot. At VP equivalent (their internal ladder is VP / Executive Director / MD), they expect you to bring up operational concerns like oncall, observability, and disaster recovery without being prompted. These are not bonus points; they are signals they're looking for.
One note on the room: it was a video call even for the "onsite." They use their own MS Teams setup. Not ideal for whiteboarding. I used a shared Google Doc and just typed out an ASCII-ish diagram. Worked fine.