Sensex and Nifty hit all-time highs of 77,145 and 23,481 respectively in early trade.

At 9:50 am, Sensex was up 173 points or 0.23 per cent at 76,788 and Nifty was at 23,370, up 46 points or 0.20 per cent.

Buying is also being seen in midcap and smallcap shares. Nifty Midcap 100 is up 269 points or 0.50 per cent at 54,512 and Nifty Smallcap 100 is at 17,824, up 27 points or 0.20 per cent.

India Volatility Index (India VIX) fell by 2.22 percent to 14.07 points.

Among sectoral indices, IT, Financial Services, Realty, Services and Metals are among the major gainers while FMCG, Media and Energy are among the major losers.

Vaishali Parekh, vice president-technical research, Prabhudas Lilladher, said the Nifty has witnessed a consolidation phase over the last three sessions, with the 23,400 zone acting as a tough hurdle to trigger further gains in the coming days. It would require a decisive breach.

"The key support zone for the index remains near 22,800 levels, while on the upside we can expect 23,800 levels as an initial target in the coming sessions," he said.

In the Sensex pack, Wipro, Tech Mahindra, Nestle, Titan Company, Bajaj Finance, HCL Tech, Kotak Mahindra Bank, Infosys, TCS and M&M are among the top gainers while Reliance, Power Grid and HUL are the top losers.