Mortgage re-pricing will add between four and five basis points to the big banks' net interest margins and as much as 3.2 per cent to their net profit, according to Deutsche Bank analysis. In a note issued on Friday, Deutsche said re-pricing will add four bps to ANZ's net interest margin and 2.5 per cent to its net profit. It will add five bps to CBA's margin and 3.1 per cent to its net profit; four bps to NAB's margin and 3.2 per cent to its net profit; and five bps to Westpac's margin and 3.1 per cent to its net profit.Deutsche's estimate is that the major banks need around 20 basis points of re-pricing across their entire mortgage books to offset the drag on return on equity from the Australian Prudential Regulation Authority's imposition of a higher capital requirement for residential mortgages.The combined effect of the re-pricing of their owner-occupier books with the earlier re-pricing of their investor loan books has achieved that offset.The increase in mortgage risk weights from 16 per cent to 25 per cent applies to authorised deposit-taking institutions accredited to use the internal ratings-based approach to credit risk - the big banks plus Macquarie Bank.Deutsche said APRA's demand for top quartile capital levels could leave some residual ROE pressure.