...but I can't seem to find the exact answer. If a customer brings in cash to purchase a cashier's check, we have them deposit it to their account first, then debit for the check (making a good paper trail). Question: If the amount is over $10,000 cash, would you mark the CTR (section II) as a deposit and MI purchase both? or just MI purchase? Thanks folks!

I doubt you'll find an official answer, but the reportable transaction that actually took place was a deposit. That's the box I would check. If the CTR makes someone curious enough to look at the account they will find the purchase of the offical check.

Thanks Ken, that makes sense. Appreciate the reply.