A higher impairment charge dented the June quarter profit of Westpac, with the bank taking the opportunity to tidy up it problematic assets, which it says it has done in the third quarter of previous years.The A$770 million of lending losses recognised in the quarter were more than double those of the first two quarters combined.The approach appeared to catch some investors off-guard, with the trading update being the trigger for a decline of four per cent in the share price of Westpac yesterday, while the prices of other major banks sagged by a little less than one per cent, in line with the ASX200.The bank said its cash earnings for the June quarter fell two per cent, to $1.55 billion, while earnings before bad debt charges and tax increased by two per cent.Westpac said its margin increased by four basis points over the quarter, from 2.08 per cent in the first half. The bank said the balances of high interest online accounts were lower over the quarter, assisting the margin, and this trend may be improving as term deposit yields are falling at a time when deposit flows are fully funding lending growth.The Pillar 3 report for the quarter shows that impaired assets fell three per cent, to $4.6 billion. Loans 90 days past due fell by a third of a per cent, to $3.6 billion.