The Sensex at the Bombay Stock Exchange, which had opened 135 points higher, to again cross the psychological 20,000 level, this morning, later firmed up further, to stand 171 points, or 0.9 percent in the green, at 20,138, in afternoon trade, a short while ago. Fresh buying by funds, amid largely positive regional markets, helped lift the domestic bourses. Stock markets in China, Hong Kong, Indonesia, Singapore and Taiwan were up by between 0.4 percent and to 0.9 percent. But the key benchmark indices in Japan and South Korea were down by about 0.2 percent, each.