The benchmark BSE Sensex today staged a strong comeback to close 321.73 points higher on across-the-board buying in blue-chip stocks by funds and retail investors on rate cut hopes and value-buying.

Further, beginning of June series in the derivatives segment, supported the upside in stock prices.

The 30-stock index opened on a positive note at 27,553.03 but quickly slipped into the red on profit-booking. Later, it bounced back at a rapid pace to hit the day's high of 27,888.32 on beginning of June series in the derivatives segment.

The gauge settled 321.73 points or 1.17 per cent higher at 27,828.44, its strongest rally since May 18.

On similar lines, NSE Nifty recaptured the 8,400-mark by rising 114.65 points or 1.38 per cent to 8,433.65 after hovering between 8,443.90 and 8,305.70, intra-day.

Revival of value-buying by investors as recent fall was excessive, too influenced sentiments, they said.

Bharti Airtel at 5.98 per cent was the best Sensex gainer, followed by M&M 4.89 per cent, GAIL 2.30 per cent, Maruti Suzuki 2.26 per cent and Coal India 2.14.

Sentiments bolstered on renewed hopes that the Reserve Bank of India may cut rates in its policy review and beginning of new series in the derivatives segment, triggering buying by participants, brokers said.

Of 30-Sensex shares, 26 ended higher, while 4 ended lower. Among BSE sectoral indices, auto index gained the most by rising 2.08 per cent, followed by infra (1.84 per cent), healthcare (1.63 per cent), bankex (1.45 per cent), oil&gas (1.32 per cent) and capital goods (1.23 per cent).

Buying activity also re-emerged in the broader markets with the BSE mid-cap index rising 1.48 per cent and small cap gaining 1.22 per cent.

Meanwhile, foreign portfolio investors sold shares worth Rs 792.54 crore, while Doemstic Institutional Investors bought shares worth Rs 683.29 crore yesterday, as per provisional data.