Equity benchmarks Sensex and Nifty opened on a choppy note on Thursday ahead of the expiry of monthly derivatives amid a largely weak trend in Asian markets.

After opening on a positive note, the 30-share BSE index slipped into red to trade 67.33 points or 0.13 per cent lower at 50,950.19, and the broader NSE Nifty fell 11.20 points or 0.07 per cent to 15,290.25.