PNB Housing Finance on Monday reported a 4.3% rise in first quarter net profit at Rs 557 crore as compared with Rs 534 crore in the year ago period even as its loan assets expanded 15% year-on-year to Rs 89670 crore.The lender's net interest margin for the quarter compressed 24 basis points to 3.5% from 3.74% seen in the year-ago period. Gross non-performing assets ratio improved 11 basis points to 0.95% from 1.06% a year prior.Its assets under management stood at Rs 93,021 crore at the end of June, reflecting a 13% year-on-year rise.Profit before tax stood 4.4% higher at Rs 718 crore against Rs 688 crore, on a total income of Rs 2265 crore which rose about 9%. Expenses for the quarter rose 11% at Rs 1547 core.