seems ok, without seeing tables and data its hard to tell in absolute certainty. What I often do to build confidence in my queries, especially with these that aggregates data in groups, is to verify a few groups in isolation with simpler queries that should be obviously correct. I've done this often and its saved me some embarrassment that would happen if I shipped the malfunctioning query.

Like pick just one region and trader and verify that the number of trades matches whats calculated in your grouping query for the same criteria, and repeat as many times as you can imagine, especially if you can find some special cases that might be tricky. Also if theres any nulls anywhere watch for those cases, especially since you're left joining to the users.

I can certainly understand your concerns about accuracy, bugs and misunderstandings can often come out of left field and I've caught out a few mistakes from even the most confident of query writers, including me LOL