I currently work at an all student run credit union that has the same rules as any other bank in regards to ACH transactions so I think I can clarify some point

I currently work at an all student run credit union that has the same rules as any other bank in regards to ACH transactions so I think I can clarify some points here. Institutions are allowed up to 5 business days to accept or reject an ACH based debit or credit if it is between non-local banks. However, business days are really the days in which the Fed are open. So there are days when you could potentially have to wait up to 8 days for a transfer to be completed (ie 5 business days + weekend + holiday). If it is between local banks which is defined as being in the same Fed region, the rule is 3 business days. These rules are very outdated and need to be updated. I think this is one of the most hindering rules in the current financial system. Back in the day, I could see the need for there to be different time allotments between local and non-local transactions, but today it is pretty much instantaneous. However, I don't see these regulations being changed in the near future and the reason is very simple. Big banks have more time to use this "float" money to make money, as well as to secure the money via overnight loans if they are short. Thankfully, most banks process ACH twice daily (morning and night), but not all. And some even delay transactions on purpose. Also if anyone is curious how much money it really costs a bank or credit union to do a ACH transfer, it is $0.000133 per transaction. So when your institution charges you $5 or $15 or even $25 to do a incoming or outgoing transfer, they are literally making bank.