Key stock market indices on Tuesday failed to sustain the buying momentum witnessed in early trade and gave up their gains to close in the negative territory.  The S&P BSE Sensex which opened 222 points higher than the previous day’s close surged to its intraday high of 7,9795 points but soon lost ground and settled at 78,593, down 166 points or 0.21%.  With a loss of 1.77% M&M was the top loser in the Sensex followed by State Bank which shed 1.65%. The NSE Nifty-50 too fell 63 points or 0.26% to 23,992.55.   “Indian markets started the day on a positive note Tuesday, buoyed by a rebound in other Asian markets, notably Japan, which had experienced their worst downturn since 2008. However, the momentum faded, and about an hour and a half before the close, the markets gave up their gains,” said Avdhut Bagkar, Technical and Derivatives Analyst, StoxBox. “The BSE Sensex and Nifty ended at their lowest levels since June 25,” he added.  The Indian Rupee on Tuesday gained 17 paise on the spot market to close at 83.92 against the US Dollar from its over night close of 84.09.