Stock markets declined for a second day in a row on Wednesday with benchmark Sensex closing lower by 536 points due to selling in HDFC Bank and IT shares amid weak global trends. The 30-share BSE Sensex fell by 535.88 points or 0.75 per cent to settle at 71,356.60. During the day, it tumbled 588.51 points or 0.81 per cent to 71,303.97. The broader Nifty of the National Stock Exchange slipped 148.45 points or 0.69 per cent to 21,517.35.