The rupee dropped 4 paise to 86.72 (provisional) against the US dollar on Monday amid a steep fall in the domestic equity markets and a rise in Brent crude prices. However, a flat greenback against major currencies prevented further decline in the domestic unit, according to forex traders. At the interbank foreign exchange, the local unit opened at 86.58, went up 10 paise from Friday's close of 86.68, but gave way through the session. It eventually settled at 86.72 (provisional), 4 paise lower than the previous day's close. "The RBI is all set to do a 3-year buy/sell swap of USD 10 billion on February 28 to ease the tightening liquidity position, thus bringing premiums further down. Exporters may sell the cash dollars requirement on all upticks while importers may buy good dips," Anil Kumar Bhansali, Head of Treasury and Executive Director, Finrex Treasury Advisors LLP, said. Meanwhile, the dollar index, which gauges the greenback's strength against a basket of six currencies, was