The BSE benchmark Sensex today gained by nearly 92 points in early trade on fresh buying by funds and retailers ahead of industrial output data amid a firming trend in other Asian bourses.The 30-share barometer rose by 91.65 points, to 19,478.79. It had lost nearly 100 points in the past three sessions. Similarly, the wide-based National Stock Exchange index Nifty moved up by 25 points,to 5,924.60.