The rupee firmed up by 11 paise to 66.50 against the dollar in early trade today, maintaining its upward trend for the fourth straight day on sustained selling of the US currency by exporters and banks amid a higher opening in the domestic equity market.

Forex dealers said weakness in the dollar against other currencies overseas supported the rupee. A higher opening in the domestic equity market gave the uptrend some momentum, they added.

On Monday, the domestic unit ended higher by 4 paise against the dollar at 66.61.

Meanwhile, the benchmark BSE Sensex rose 138.46 points, or 0.48 per cent, to 28,432.74 in the early session.