The latest data on Basel III leverage ratios for Asia-Pacific's biggest banks by assets shows Australia's Big Four banks sitting among the majority of large banks in the region, having raised their leverage ratios in the first half of 2017 from a year ago. For example, the data shows Westpac's leverage ratio increased by 29 basis points to 5.30 per cent at the end of June. The ratio is calculated by dividing a bank's Tier 1 capital by its total leverage exposure. Under Basel III, the ratio takes into account both on-balance-sheet and off-balance-sheet exposures.