【明報專訊】TO get business, banks have vied with one another to cut mortgage rates. It is said that, to end the cut-rate war, the Hong Kong Monetary Authority (HKMA) has set the lowest permissible mortgage rate. It may have done so with the object of maintaining Hong Kong's financial stability. However, to do so is to tell banks how to do business. That exceeds the HKMA's functions. Furthermore, the move may give banks an unfair advantage. It may encourage them to conspire together to set prices to guarantee their profits. That would be unfair to citizens.