Answer
At the outset, we wish to state that it is not permissible to take an
interest bearing loan as is the case in an overdraft situation. It is not
permissible to accumulate funds to generate interest.
However, the accumulated interest on funds may be used to offset interest
charged from the same bank, for example, both accounts are in Standard Bank.
If one account in Standard Bank and the other is at another bank, the
interest earned from one cannot be used to offset interest charges at
another bank.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai