The 30-scrip sensitive index (Sensex) of the S&P Bombay Stock Exchange (BSE), which opened at 20,522.36 points, was trading at 20,558.04 points in the pre-noon session, up 137.78 points or 0.67 percent from the previous day's close at 20,420.26 points. The Sensex touched a high of 20,606.38 points and a low of 20,517.97 points during the trade so far.