Weakening credit quality among Asian corporate borrowers in general, and Indonesian manufacturers in particular, proved a thorn in ANZ's trading update for the December 2015 quarter, released yesterday.ANZ said the credit charge for the March 2016 half year "will be a little above A$800 million," which is equal to two-thirds of the charge incurred over the full year to September 2015.In an interview with the bank's BlueNotes portal, ANZ chief executive Shayne Elliott said: "What we saw at the beginning of this calendar year is that [the credit cycle's] been a little bit more volatile than we were expecting and some of those conditions have been a little bit more difficult."It tends to hit in the manufacturing base across Asia Pacific, which today is in south-east Asia, most predominantly Indonesia. And that absolutely is having an impact in terms of our credit books. "And we've started to see that in the recent weeks and we've flagged that in our result update."Elliott added that it was "broadly based." "It's not one customer group in particular or anything like that. But it does tend to be concentrated around manufacturing, kind of industrial companies and those exposed to trade," he said.The bank, in tandem, has continued dialling down on trade finance, a segment in which it had been enthusiastic in the recent past.Among the scant metrics included in the trading update ANZ said there was a two basis point decline in its net interest margin, to 202 basis points.ANZ said its net profit for the quarter was $1.6 billion, meaning that over the first quarter of its current financial year the bank produced a profit equal to around one fifth of that earned in 2015.The net profit for the current quarter is also less than the $1.65 billion profit earned in the corresponding quarter at the end of 2014.