Westpac's net interest margin revealed as much, falling 11 basis points over the year, although the pace of the fall started to slow in the second half. Given that Westpac has much less exposure to business lending than its rivals, it has fewer levers to pull when it comes to margins. In contrast, players such as National Australia Bank and ANZ have been able to protect their margins mostly by repricing business loans. However, with a large and low-risk mortgage book, Westpac's profit growth is skewed to the medium term with the bank expected to benefit when wholesale funding and deposit costs begin to stabilise.