The Bombay Stock Exchange benchmark Sensex on Friday gained 55 points in early trade on fresh buying by funds.The 30-share index rose by 54.98 points to 17,639.85 in the first five minutes of trade, continuing with its gains for the third straight day. On Thurday the index had closed 75 points up at 17,584.87. The wide-based National Stock Exchange index Nifty rose by 19.95 points at 5,279.85 points at the same time. On Thursday, The Dow Jones Industrial Average had gained 0.1 per cent to 10,690.90 and the Nasdaq Composite was also up 0.1 per cent higher at 2,310.58.