The industry's capital adequacy ratio has bounded one percentage point to 14.1 per cent over the course of 2016.The Australian banking industry lifted its capital base by $16 billion or seven per cent to $272 billion over the last year.The sector's capital adequacy ratio straddled new heights at 13.9 per cent at the end of the year, a marked difference on the mid ten per cent levels common in the period ahead of the great recession. APRA reports that for credit unions this ratio is 16.3 per cent, a capital strength measure with longevity, common for Australian mutual ADIs since the GFC, APRA reports.The build-up in industry capital levels is nothing radical and any call by Australian banks as a consequence of APRA's new guide on capital buffers may prove simple to accommodate.Looking at the annual growth in industry capital levels in the APRA record (which dates from 2004), if there was a spirited call for help it shone through in the second half of 2007, when capital level growth (year on year) touched 20 per cent.Things got heated again in 2009 and they are heating up again once more, thanks to APRA. Michael Cunningham, an advisory partner in financial risk management at KPMG and a prolific commentator for the firm, asked in an email:"In the quest for 'unquestionably strong' banks capital levels, would APRA lift the buffer for the D-SIBs to more than 3.5 per cent? "Relatively the D-SIB buffer for Oz majors looks light versus some of the G-SIB buffers, and APRA said in its July 2014 submission to the Murray Inquiry that 'the major banks look more systemic in the domestic context' than the G-SIBs looks in the global context. "Additionally, what 'excess growth' is required to trigger a countercyclical buffer change? Is six per cent mortgage growth excessive, or would it need to be back at below 11 per cent, like it was pre-2008? "And would they apply a countercyclical buffer if growth in one segment was excessive, but total growth was within their 'limits' - for example, mortgage growth at 11 per cent, but total growth of below five per cent as business loan growth flat-lined?"