Markets traded volatile on the day of monthly F&O expiry. RBI’s warning of the risk of a bubble in the equities made the markets cautious. The BSE Sensex ended at 51,115.22, up 97.70 points or 0.19%. The Nifty still could not hit record high. The 50-share closed at 15,337.85, up 36.40 points or 0.24%.