"Also worth noting that banks love to process debits before they process credits so you could have 100 units of money in yoru account with another 200 going in and 200 going out. You will then see that on your statment that they have the 100 then the -200 and then the +200, so indicating that you are -100 for a period, evil are they not."

I've had this happen to me, and a few years ago I happened to work for a short time with someone who had formerly been the president of a small regional bank. He confirmed that some banks do intentionally do that, and that many of the banking software systems had configuration options to decide what order to process data (debits or credits first) and that banks looking to make more money could just flip that switch and start raking in more fees.

It's really annoying to have people say that it doesn't happen when a) I've had it happen to me and b) I've had it confirmed by a banking executive.

Any modern bank will process deposits before withdrawal, or process them in order of entry. With the introduction of ATMs, the order of operations during the day by the customer could have been:

    Opening Balance: 100
    Withdraw 50 --> 50
    Deposit 200 --> 250
    Withdraw 150 --> 100

At no time were they overdrawn. Evil Bank® would have done as you suggested, with the reconciliation at the end of the day being the old paper-based approach of:

    Opening Balance: 100
    Subtract sum of Withdrawals: 200 --> -100
    Subtract penalties: 50 --> -150
    Add sum of Deposits: 200 --> 50

KeyBank assessed me $360 of overdraft fees for a single day for a similar thing, where a check/cash was deposited (and it wasn't related to check deposit policy, that much was multiply verified in the arguments with various managers), and I went shopping with my partner for Christmas afterwards.

I'm no longer a KeyBank customer (in between that and them cancelling my card for a $1 Roku pre-auth charge as 'suspicious' - but not notifying me, calling, etc, just popping a letter in the mail which arrived three days after I discovered for myself it was cancelled), unsurprisingly, as they refused to budge on waiving the fees (except for one - "you get one courtesy fee waiver per calendar year". The mind boggles).

Further some banks in the US were found to sort debits by descending amount prior to processing. Allegedly this was done in the event that the account was overdrawn, fees were maximized since more transactions would occur after being overdrawn.

I believe this resulted in class action law suits, and regulations preventing this behavior, but I can't find any news article about it at the moment.

> Also worth noting that banks love to process debits before they process credits so you could have 100 units of money in yoru account with another 200 going in and 200 going out. You will then see that on your statment that they have the 100 then the -200 and then the +200, so indicating that you are -100 for a period, evil are they not.

Worth noting that is not the case in countries != America, and is in fact illegal in many countries.