In volatile movements, the 30-share gauge opened on a strong footing but succumbed to profit-booking and slipped into the negative zone to touch a low of 28,622.44.
"Initially, we saw an uptick in index in response to rating upgrade from Moody but profit taking at higher levels capped the upside for most part of the session," said Jayant Manglik, President-retail distribution at Religare Securities.
The Sensex has now garnered over 927.72 points in five sessions and is at nearly one-month high. The previous high was on March 12 when it ended at 28,930.41.
The 50-share NSE Nifty index spurted by 63.90 points, or 0.73 per cent, to close at 8,778.30. During the session, it shuttled between 8,785.50 and 8,682.45.
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Showing confidence in the Indian economy, Moody's raised country's credit rating outlook and said an upgrade in its sovereign rating is also possible in the next 12-18 months.
Strong rally in BSE Sensex heavyweight RIL and banking shares like HDFC Bank, ICICI Bank, Axis Bank and SBI together contributed most of the gains.
In the banking space, prominent gainers were PNB at 6.03 per cent, IndusInd Bank 4.63 per cent, Kotak Bank (4.16 pc), Bank of India (3.15 pc), Axis Bank (2.88 pc), Yes Bank (2.67 pc), SBI (2.50 pc), Canara Bank (2.48 pc), Bank of Baroda (2.40 pc), HDFC Bank (1.68 pc) and ICICI Bank (1.65 pc).
However, fall in Sun Pharma, Cipla, Bharti Airtel and GAIL restricted the surge to a certain extent.