I go to two different banks nearly every day to make deposits for work. One of the banks, the first time you make a deposit asks for your ID and SSN. They did it to me years ago, if I send an employee to make the deposit they’ll do it to them. So far as I know, they haven’t changed their policy, but they do make note of who makes the deposit. That they know me by name is why they don’t ask for my ID. If know one there knew me (ie different tellers), they’d probably ask for it again.
The other bank I go to (US Bank) starting earlier this year began asking for my ID almost every single time (I believe if there’s more than 500 in cash involved). Some of these tellers I’ve known for nearly 20 years (from going to this branch). One time I was speaking with the branch manager and asked about this. I mentioned that one of the reasons this annoys me so much is because I keep losing my ID. That is, I need it for something and suddenly remember it’s at work, stuffed into a bank bag. Also, for a few weeks the owner lost his wallet. I asked them about that and they said he would’t be able to make a deposit. That seems over the top, the owner of the business, the person who’s name is on the account, that the tellers have known for decades can’t make a deposit into his own account.
Anyways, to swing back around to the OP, one of the things they always ask, in addition to getting my ID is ‘what is your job’? That kind of annoyed me, I get needing my ID, but my job. Naturally I said ‘uh, I work for the business that I’m making the deposit for’. Nope, they wanted to know what I do there. So I’d reply with ‘I bring the money to the bank’. Some said ‘ok’ some through a little hissy fit. At that point I started changing my ‘job’ each time. "I mop the floors’ or ‘I do all the roof repairs’. One of the times the teller said ‘that’s not one of the options’, at which point I said ‘all this time you have options to pick from, just tell me what they are and I’ll pick one’.
Anyway, yes, it’s just anti-money laundering. It gives them the ability to track who made the deposits. I’m sure if the IRS or FBI shows up, it just gives them more people to talk to even though many small businesses (even if they’re laundering money) just send random employees to the bank that likely have nothing to do with anything.
Also, you can no longer get a cashier’s check without depositing the money into your account and having them write the check off that. Same reasons, I assume.
TLDR, banks have to fill out a form if a withdrawal is over a certain amount. If it’s below that amount the can/should still do it if it’s ‘suspicious’. They’re also know IDing people for all deposits.