The Bombay Stock Exchange (BSE)'s Sensex gained 20 points on the first day of new settlement while S&P CNX Nifty was marginally up by 3 points on Monday. The Sensex opened with a positive gap at 4363.79 and moved upwards to 4378.06, which happened to be intra-day high, and receeded from this level as operator resorted to profit-taking as they failed to take any trigger from bigger players. It touched the day's low of 4302.10 before closing at 4350.65, a gain of 20.33 points. Nifty also followed suit and closed at 1384.55, as compared to the previous close of 1381.35, gaining 3.2 points.