Westpac owned up yesterday to under-reporting its credit exposure in the home loan sector.In the past the bank had not fully reported the credit it was contracted to supply to borrowers with a home loan with a redraw option, which would have to be at least half the portfolio and maybe a lot more.Maybe the bank modelled the exposure to recognise it in some fashion, since it was never likely every home loan customer would want to redraw every last dollar at the same time.But at someone's initiative - and who? - the bank has now recognised this credit exposure in full. Chief financial officer Phil Chronican said this would double the level of off balance sheet exposure for home lending, though it would have a trivial effect on allocated capital for home lending.This additional exposure could well be an example of other under-reported credit exposures that will emerge as the Basel 2 and Pillar 3 approaches make an impact on reporting practices and stakeholder understanding.Meanwhile Westpac put 90-day overdue home loans in Australia at 42 basis points, up seven bps since September. Overdue consumer loans were 99 bps, up six bps.