Equity benchmark BSE Sensex zoomed 637 points on Wednesday, driven by gains in banking stocks ahead of finance minister Nirmala Sitharaman's press conference to unveil provisions of the Rs 20 lakh crore stimulus package announced by the government.

Prime Minister Narendra Modi's announcement of the massive economic stimulus to revive the coronavirus-hit economy boosted domestic investor sentiment, traders said.

After rallying 1,474.36 points during the day, the 30-share index surrendered some early gains to settle 637.49 points or 2.03 per cent higher at 32,008.61.

Similarly, the NSE Nifty jumped 187 points, or 2.03 per cent, to finish at 9,383.55.

Axis Bank was the top gainer in the Sensex pack, surging around 7 per cent, followed by Ultratech Cement, L&T, ICICI Bank, SBI, M&M and Bajaj Finance.

On the other hand, Nestle India, Sun Pharma, Bharti Airtel and HUL ended in the red.

The Prime Minister on Tuesday announced a massive new financial package on top of the previously announced measures for a combined stimulus of Rs 20 lakh crore.

He said the package will be around 10 percent of the GDP and 'will play an important role in the 'Atmanirbhar Bharat Abhiyan' (self-reliant India campaign)', adding that the 'announcements made by the government so far, the decisions of the RBI and today's package totals to Rs 20 lakh crore.'

The special economic package will have emphasis on land, labour, liquidity and laws, and will be for 'our labourers, farmers, honest tax payers, MSMEs and cottage industry', Modi said.

On the currency front, the rupee appreciated by 5 paise to provisionally close at 75.46 against the US dollar.

Meanwhile, bourses in Shanghai and Seoul ended with gains, while Hong Kong and Tokyo closed in the red.

Stock exchanges in Europe started off with significant losses.

International oil benchmark Brent crude futures slipped 1.30 per cent to USD 29.59 per barrel.