If you initiate an ACH bank-to-bank transfer when you're logged into your internet bank, that ACH transfer will often take 2 to 5 business days to complete. Why can't it be done in one day?
Many of us have speculated that it's due to the profits banks make from the float. The blog Bankwatch which tracks financial services makes this claim in this blog post:
Bank choose to hold on to money that is ‘wired’ because that float as it is known in the industry is very lucrative. The funds are invested overnight(s) and so long as all the banks co-operate by not unwinding that practise they retain that unearned profit. Sure all the excuses are rolled out (ensure funds are cleared, reduce potential for fraud, allow for funds recall) but it is a smoke screen. The profits generated by float need to be replaced by exemplary service that warrants a suitable fee.
Bankwatch also highlighted a new electronic transfer service provided by Dwolla called FiSync. As described in this Dwolla blog post, it offers real-time transfers.
This Dwolla service would be great for consumers, but according to this Bankwatch post, it's unlikely to be accepted. There's an interesting table in that post showing how much profits there are in the float.