The BSE benchmark Sensex extendedgains for the second straight day by adding over 83 points in early trade today.The 30-share index, which had gained over 199 points in the previous session, added another 83 points, or 0.51 percent, to 16,500 with all the sectoral indices led by auto were trading in positive zone.The wide-based National Stock Exchange index Nifty, regained crucial 5,000 points level by rising 19.70 points, or 0.40 per cent.In the Asian region, the Japan's Nikkei was down 0.06 per cent, while Hong Kong's Hang Seng marginally up by 0.18 per cent in the morning trade today.