Your salary must be paid into the account and you must pay interest (which is calculated daily) at a current rate. At the same time, the One account is run like an ordinary bank account (you get a chequebook and bank cards and there are no restrictions on the number of withdrawals) On the face of it, only a fool would put his money into one bank earning interest at, say 6%, and then borrow the same amount from another bank at 10%. But this is precisely what most people are doing they are funding mortgages at rates much higher than they are getting for their savings. And for much of the time, they are not getting any interest at all on money in their ordinary bank accounts.