The Bombay Stock Exchange benchmark Sensex gained over 120 points in early trade on Wednesday. Extending its gains for the fifth consecutive session, the 30-share BSE barometer rose by 120.04 points, or 0.65 per cent, to 18,612.49 in the first few minutes of trade on Wednesday. Similarly, the broad-based National Stock Exchange Nifty index moved up by 35.50 points, or 0.59 per cent, to 5,557.90.