I agree with what you are saying in principal. My initial thought was that rewarding savers is the opposite of what the Central bank is trying to do. And there is only one target rate to adjust, the OCR, which interest rates to savers and borrowers are based from. It is only the retail banks who alter other rates based on supply and demand. Seems the retail banks have only given term deposit savers a boost in the latest increase which in essence rewards locking away money.
