The Sensex opened higher at 28,912.38 and hovered in a range of 29,054.26 and 28,824.88 before quoting at 28,997.81 at 1100 hours, showing a gain of 114.70 points, or 0.40 per cent, from its last close.
The CNX 50-share Nifty also firmed up by 30.45 points, or 0.35 per cent, to 8,754.15 at 1100 hours.
In the foreign exchange market, the rupee edged lower against the dollar.
A weak rupee boosts revenue of IT firms as the sector derives a major share of its revenue from exports.
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Meanwhile, foreign portfolio investors sold shares worth a net Rs 83.80 crore yesterday, as per provisional data.
Among overseas markets, Asian stocks edged lower after the European Central Bank (ECB) yesterday pulled back its soft treatment of Greek debt and cancelled its acceptance of the country's bonds in return for funding.
Key indices in Taiwan, Singapore and South Korea were off between 0.33-0.67 per cent while Hong Kong's Hang Seng was up by 0.44 per cent.