Mumbai, Feb 23 (PTI) The rupee surged by 21 paise to 90.73 against the US dollar in early trade on Monday, aided by a sharp fall in global crude oil prices and a weaker greenback amid renewed uncertainties over US President Donald Trump hiking tariffs to 15 per cent.

Brent crude, the global oil benchmark, was down 1.09 per cent at USD 70.98 per barrel.

A strong opening in domestic equity markets, along with a jump in forex reserves, provided further support to the local unit, according to forex traders.

At the interbank foreign exchange, the rupee opened at 90.76 against the US dollar and rose further to 90.73, up 21 paise against its previous close.

The rupee plunged 26 paise to settle at 90.94 against the US dollar on Friday.

"The rupee opened stronger after the US Supreme Court's decision on tariffs caused the dollar index to fall. Most Asian currencies have gained from their Friday close," Anil Kumar Bhansali, Head of Treasury and Executive Director, Finrex Treasury Advisors LLP, said.

He, however, said dollar buying sentiment continues in the market and could weigh on the rupee. "The rupee could be sold off as the day passes with dollar-buying sentiment continuing in the market," he said.

Meanwhile, the dollar index, which gauges the greenback's strength against a basket of six currencies, was trading lower by 0.33 per cent at 97.47.

On the domestic equity market front, Sensex surged 621.78 points to 83,436.49 in early trade while Nifty was up 180.05 points to 25,751.30.

On Friday, foreign institutional investors offloaded equities worth Rs 934.61 crore, according to exchange data.

India's forex reserves jumped USD 8.663 billion to hit a new all-time high of USD 725.727 billion in the week ended February 13, the RBI said on Friday. PTI TRB MR

Foreign exchange volatility: rupee strengthened after oil-led dollar weakness, while reserve gains and capital flows shape market risk. The rupee strengthened in early trade due to lower global crude prices and a softer dollar amid tariff-related uncertainty, aided by a strong equity opening; persistent dollar-buying sentiment and foreign institutional outflows could reintroduce selling pressure. The Reserve Bank of India's rise in foreign exchange reserves to a record level is a material macroprudential indicator affecting market liquidity and perceived intervention capacity under FEMA and central bank reserve management frameworks.