The Bombay Stock Exchange benchmark Sensex today rose by 75 points in opening trade on fresh buying by funds and retail investors. The 30-share index rose to 17,176.6 points. The wide-based National Stock Exchange index Nifty also moved up by 22.40 points to trade higher at 5,131.30 points. IT, auto and banking stocks were major gainers, which helped Sensex trade in the positive zone. Brokers said fresh buying by funds and retail investors, and covering-up of short positions by speculators influenced trading sentiments.