The rupee witnessed a range-bound trade and strengthened marginally by 4 paise to 84 (provisional) against the US dollar on Wednesday as easing crude oil prices supported investor sentiments. Rupee traded in a narrow range as a strong dollar and a muted tone in the domestic equities weighed on the local unit, while weak crude oil prices supported the local currency at lower levels. The benchmark 30-share BSE Sensex ended the session down 318.76 points, or 0.39 percent, at 81,501.36 while the broader NSE Nifty index settled at 24,971.30, down 86.05 points, or 0.34 percent, from its previous close. At the interbank foreign exchange market, the local unit opened at 84.03 and traded in a narrow range of 83.98 and 84.07 and finally settled for the day at 84.00 (provisional), higher by 4 paisa over its previous close of 84.04 against the dollar.