Maintaining its upward trend,the Sensex at the Bombay Stock Exchange was trading 107 points in the positive territory at 18,852 in afternoon trade, when reports last came in. The 30-share index, which had gained over 500 points in the previous two sessions, rose by 80 points in early trade today.The Nifty at the National Stock Exchange was trading 38 points in the green at 5,727.