Benchmark equity indices bounced back sharply and ended in the positive territory on Monday, helped by fag-end buying in index heavyweights Reliance Industries and Infosys along with a firm beginning in European markets. The 30-share BSE Sensex climbed 79.27 points or 0.12 per cent to settle at 65,401.92. During the day, it fell 500.77 points or 0.76 per cent to 64,821.88. The NSE Nifty gained 6.25 points or 0.03 per cent to end at 19,434.55.