[fuzztester]

Same for database transaction roll back and roll forward actions.

And most enterprises, including banks, use databases.

So by bad luck, you may get a couple of transactions reversed in order of time, such as a $20 debit incorrectly happening before a $10 credit, when your bank balance was only $10 prior to both those transactions. So your balance temporarily goes negative.

Now imagine if all those amounts were ten thousand times higher ...

[ill13]

To clear, most banks "sort" transactions from to high to low to create more NSF fees on purpose.

That purpose equates to over $12 billion in fees for 2024

https://finhealthnetwork.org/research/overdraft-nsf-fees-big...

[ssl-3]

Awful stuff.

I was just starting off in life (kid, girl, job, apartment, bank, debit card, bills) when I made a 63-cent error with my bank account. Which is to say: If all of the negative debits and all of the positive credits were summed, then the account would have been in the negative by 63 cents.

I screwed up. And in a fair and just world, I'd owe the bank some extra tithing for quite clearly having spent some money that I very definitely did not have. Maybe $20 for the error and $10 per day spent in the red, plus the 63 cents, or something along those lines.

But it wasn't that way. Because the transactions were processed in batches that were re-ordered to be highest-first, I discovered that I owed the bank a little more than $430.

At the time (around 25 years ago, now) that was an absolute mountain of money to me.

The banker at the branch I went into was unapologetic and crass about the fees.

Looking over my transactions, they said "You know how to do math, right? You should have known that the account was overdrawn, but you were just out spending money willy-nilly all over town anyway."

I replied with something like "I made a single error of 63 cents. The rest of what you said is an invention."

This went back and forth for a bit before I successfully managed to leave the building without any handcuffs, fire trucks, or ambulances becoming involved -- and I still owed them more than $430.

The lesson I learned was very simple: Seriously, fuck those guys.

($12 billion in 2024, huh? That's all? Maybe the no-fee fintechs are winning.)