The Indian equities benchmark opened on a negative note on Friday against the indication of the SGX index. At 9:21 am, the 30-share BSE Sensex was trading 215 points or 0.42 per cent lower at 51,280, whereas the NSE Nifty 50 index declined 86 points or 0.56 per cent at 15,274. On Thursday, Sensex plunged to a 52-week low of 51,425, whereas the Nifty 50 index declined to its 52-week low of 15,335.