How large an amount? Even on £100k, you've only "lost" £10 (£5 a day).Try Premium Bonds, you get burned on the way in and again on the way out!
I believe the BACS system is used by organisations that want to do a large number of payments each day - it probably would be impractical to do that number of faster payments each day.So during the day, as people request withdrawal of their money or whatever, the organisation (eg NS&I) build a file of 'transfers' which obviously gets larger and larger as the day progresses. They then submit this file to their bank before the BACS cut off date.So:Day 1 - NS&I have the financial benefit as they haven't done anything other than build and submit a file to process.Day 2 - NS&I's bank get to work processing the file, debiting NS&I's account and sending the money to the banks of their customers. So day 2, the customer's banks have the financial benefit.Day 3 - the money is finally moved to the customer's account.
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