I just felt I had to chime in, I work in a bank and get complaints such as those daily...

First, just want to demystify something : No bank in the world invests money they use for transfers...it is forbidden and much too dangerous...

Usually, the delay between the debit of the account and the credit on the other side is a security for the bank...See when you transmit your order online, it goes to your bank's payment center, where it is checked to see wheter any important information is missing, and if there is sufficient money in your account etc etc...Then they proceed to debit your account and send it to the general account of the other bank. That bank's traffic payment center then has to check wheter all the information is correct, I.E. correct customer name, correct account number...then they credit the beneficiary's account...All that takes time, especially when a manual intervention is required (like small corrections of obvious mistakes, for instance a 3 instead of an 8 in an account number)

In Switzerland, all payments inland must clear within two days, but most are executed on the same day. I'm sure there is a law in the US stating how long a payment should take to clear...

I'm guessing, in your case, something probably took a bit longer than usual, but it can simply be the other bank's payment center being buried in work, it happens sometimes...