Mumbai, Aug 12 (PTI) The rupee depreciated 9 paise to 79.71 against the US dollar in opening trade on Friday, tracking the strength of the American currency in the overseas market and rising crude oil prices.At the interbank foreign exchange, the rupee opened at 79.67 against the US dollar and lost further ground to 79.71, registering a decline of 9 paise over the last close.On Thursday, the rupee depreciated by 37 paise to close at 79.62 against the US dollar.According to Anil Kumar Bhansali, Head of Treasury, Finrex Treasury Advisors, the Indian rupee depreciated on Thursday, despite a fall in the dollar index and a rise in Asian currencies, amid heavy buying of the US dollar by the government, defence and oil companies."The demand may continue on Friday due to holidays in the next week. The range for the day is between 79.40 to 79.80," Bhansali said, adding that oil prices, however, are hovering near USD 100 per barrel, which is a matter of concern for the rupee and current account deficit (CAD).The dollar index, which gauges the greenback"s strength against a basket of six currencies, rose 0.11 per cent to 105.20.Meanwhile, global oil benchmark Brent crude futures declined 0.48 per cent to USD 99.12 per barrel.On the domestic equity market front, the 30-share Sensex was trading 189.59 points or 0.32 per cent lower at 59,143.01 points, while the broader NSE Nifty was down 42.75 points or 0.24 per cent to 17,616.25.Foreign institutional investors remained net buyers in the capital market on Thursday as they purchased shares worth Rs 2,298.08 crore, as per exchange data. PTI DRR BAL BAL