The barometer has garnered 750.26 points in four-day gaining spree.
"The sentiments were optimistic after a RBI survey projected a higher economic growth rate for the country," said Jayant Manglik, President-retail distribution at Religare Securities.
The Sensex opened higher at 28,601.49 and traded in a wide range of 28,763.06 to 28,566.61 before finishing at 28,707.75, showing a gain of 191.16 points of 0.67 percent.
The previous high was on March 17 when it ended at 28,736.38.
The 50-share NSE Nifty also rallied by 54.10 points or 0.62 percent to close at three-week high of 8,714.10. It had last ended at 8,723.30 on March 17.
"Though Nifty is gradually inching higher with every passing day but lack of participation from the banking space is still a major concern," Manglik added.
Among Sensex gainers, Coal India topped the list by climbing 5.73 percent on reports that the government has lifted the cap on company's e-auction sales.
Rate-sensitive banking, realty and capital goods shares were also back in the action after some banks cut their lending rates, brokers said.
Foreign portfolio investors bought shares worth Rs 143.98 crore while domestic institutional investors sold shares worth Rs 326.06 crore on Tuesday as per provisional data.
Asian markets ended mixed on Wednesday as key indices in Singapore and Taiwan fell in the range of 0.14 percent to 0.73 percent while those in China, Hong Kong, Japan and South Korea rose between 0.60 per cent and 3.80 percent.
European markets were also trading mixed as indices in France and the UK moved up by 0.16 percent and 0.52 percent, respectively, while Germany's DAX was down by 0.25 percent.


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