The Indian rupee appreciated 4 paise to close at 85.64 (provisional) against the US dollar on Monday, supported by a firm trend in domestic equities and foreign capital inflows. Meanwhile, the US dollar index has slipped under 99 mark and currently quotes at 98.92, down 0.22% on the day amid caution ahead of the U.S.-China trade talks due later in the day. The Reserve Bank of India's robust monetary policy measures announced last week to boost growth also underpinned sentiments. The benchmark S&P/BSE Sensex ended the session up 256.22 points, or 0.31 percent, at 82,445.21 while the broader NSE Nifty index closed up 100.15 points, or 0.40 percent, at 25,103.20. However, elevated global crude oil prices limited rise. The domestic currency added modest gains to hit a high of Rs 85.45 per dollar during the day but eased slightly thereafter. On the NSE, USDINR pair ended marginally lower at 85.72.