Mumbai, Feb 18 (IANS): The key Indian equity indices traded on a flat note on Thursday morning amid a largely choppy trade session, after opening in the green.

Around 10.10 a.m., Sensex was trading flat at 51,702.57, lower by just 1.26 points from previous close of 51,703.83.

It opened at the intraday high of 51,903.96 and recorded a low of 51,652.67 points.

The Nifty50 on the National Stock Exchange was trading at 15,222.25, lower by just 13.35 points or 0.09 per cent from its previous close.

Manish Hathiramani, technical analyst with Deen Dayal Investments said: "The markets have been a tad nervous since yesterday. The key support to watch out for is 15,100 and until we do not close below this level, traders can accumulate long positions at the current juncture and keep a stop below the support level of 15,100. 15,500 can be a potential target."

Healthy buying was witnessed in metal, oil and gas and energy stocks, while finance, banking and telecom stocks were under selling pressure.

The top gainers on the Sensex were ONGC, Power Grid and Asian Paints and the major losers were ICICI Bank, Kotak Mahindra Bank and Mahindra & Mahindra.