The quarterly disclosure document for one of Westpac's two banking arms in New Zealand provides a window into the profit margin earned on one segment of wholesale banking activities, and which exceeds 60 per cent.Westpac, under direction from the Reserve Bank of New Zealand, is taking steps to transfer a series of business activities from its foreign bank branch to its incorporated subsidiary Westpac New Zealand. The transfer applies to five wholesale banking activities including deposits, transaction banking and lending for institutional customers; debt capital markets including loan syndication and securitisation (but excluding debt distribution) and also corporate advisory.Westpac said the revenues for these businesses in the year to September 2010 were NZ$180 million and the net profit was NZ$115 million.In the six months to March 2011 the revenue was NZ$80 million and the net profit NZ$50 million.Around NZ$5.3 billion deposits and NZ$6.5 billion in loans will be transferred, about one eighth of the assets of the branch.