[KLLions]

Generally, we didn't have/want discretion with this stuff. For clients where we would just execute buys and sells for them, the largest would be around $750k in a single trade, but during the course of a year certainly more than that [net], but I didn't have too many big losing trades in a row - if you do, clients just stop trading.
Each year, I was profitable over the entire client base that traded, ranging btw $8-15mm Net.

More usually - they had discretion and often ignored my advice, I'd say several million dollars, perhaps $12mm or so.

Now, on a straight hedge [buying puts, using forwards] the loss on the put/call purchase could be tens of Millions, but no economic loss as they had equivalent gain on other side. I spent a lot of my time meeting with clients and explaining risks of unhedged positions [say you got 500mm CAD from a sale] for USD-based investors. [And vice versa.]

One of my co-workers 'hid' losses by not closing out a client position and lost $50-100mm for a client. He was fired of course, and there was some sort of settlement with this client.