Equity benchmark indices opened in the green on Monday with Sensex up by 536.16 points and Nifty up by 153.55 points. At 9:18 am, the BSE S&P Sensex was up by 536.16 points or 1.28 per cent at 42,273.97 while the Nifty 50 was up by 153.55 points or 1.25 per cent at 12,417.10.