Surrendering all its initial gains, the Sensex at the Bombay Stock Exchange stood 111 points, or 0.6 percent in negative territory, at 19,338, in afternoon deals, a short while ago. In the morning, however, the Sensex had opened a good 93 points, or 0.5 per cent in the positive zone, at 19,542, on renewed buying by investors. The Sensex has lost more than 150 points in the last three sessions. Stock markets in Japan, China, Singapore, Hong Kong and South Korea were trading mixed on Thursday. The US Dow Jones Industrial Average had gained 0.8 per cent, overnight, after the US central bank's decision to hold short-term interest rates near zero.