Equity benchmark Sensex rallied 258 points and the Nifty reclaimed the 15,000 mark on Thursday, tracking gains in Reliance Industries, Axis Bank and TCS amid a positive trend in global markets. The 30-share BSE index ended 257.62 points or 0.51 per cent higher at 51,039.31. Similarly, the broader NSE Nifty rose 115.35 points or 0.77 per cent to 15,097.35.