The Sensex today opened higher by over 43 points on buying in auto, oil and gas, banking and oil stocks by funds. The 30-share index recovered by 43 points to 18,445 points in the first five minutes of trading. It had lost 53 points in the previous session on Friday.Similarly, the wide-based National Stock Exchange Nifty rose by 8 points to 5,542 points. Brokers said buying by funds and retail investors, though in selective stocks, helped the Sensex trade in positive zone.