[valdiorn]

It's anti money laundering regulation, and yes under no circumstances are you allowed to tip off the client that he's being investigated. You are literally obligated to lie if they ask and say there's an undetermined hold-up or something like that. If you don't you become criminally liable, even if the customer is found to not have broken any laws.

Work for a hedge fund under both US and UK regulatory authority.

[rosndo]

In practice this also makes it rather challenging to discuss non-AML issues with clients, because if you’re always willing to discuss non-AML issues it quickly becomes clear which issues are AML issues.