Rising for the third straight session, the Sensex at the Bombay Stock Exchange gained 101 points, or 0.5 percent, to close at 19,990, on continued buying by funds, on Wednesday. During the session, the Sensex had briefly regained the 20,000 mark after a gap of over three months. The Sensex had gained over 310 points in the last two trading sessions. The Nifty at the National Stock Exchange rose 26 points, or 0.4 percent, to 6,069.Stock markets in Japan, China, Hong Kong, Singapore and South Korea climbed between 0.1 percent and 0.9 percent.