Price discounting on loans across the industry is chipping away at banks' interest margins, if ANZ's trading update for the December 2013 quarter is any guide.The bank did not disclose its margin but said the group net interest margin "was slightly lower".ANZ said an "easing in deposit pricing was offset by the ongoing impacts of the lower interest rate environment and some asset pricing pressure, which was broadly based."The bank said financial performance "was in line with guidance provided at the time of the 2013 results [with] annual revenue growth for 2014 [expected to] be between four per cent and five  per cent, with expense growth of around two per cent."ANZ reported a statutory net profit for the quarter of A$1.64 billion, broadly in line with the September 2013 quarter but down from $1.75 billion in the June quarter.The December quarter profit was $300 million higher than the year before.The provision charge for the first quarter, at $191 million, reflected "lower new provision requirements, lower top-up provisions and slightly elevated levels of write-backs and recoveries", the bank said.ANZ put its level of gross impaired assets at $4.01 billion, a decline of $1.3 billion over a year.The ratio of non-performing loans as a percentage of gross loans is down to 1.19 per cent, reduced from 1.50 per cent a year before.Co-incidentally, on the same day as ANZ's update, a corporate customer, the ASX-listed mining services firm, Forge Group, called in Ferrier Hodgson as voluntary administrators, leaving ANZ to appoint KordaMentha as receivers. Forge had been supported by an ANZ line of credit, including a further loan of $11m two weeks ago, that was conditional on finding an equity backer.