Giving up all of its initial gains, the Sensex at the Bombay Stock Exchange stood 38 points, or 0.2 percent in negative territory, at 19,449 in afternoon deals, a short while ago. Earlier in the morning, however, the Sensex had opened with a gain of 75 points, or 0.4 per cent, at 19,562, on optimism about the vote on FDI in the Rajya Sabha. The 30-share Sensex had climbed over 180 points in the previous three trading sessions.Stock markets in Japan, China, Hong Kong, Singapore, South Korea, and Taiwan were up by between 0.1 percent and 1.2 percent, today. The US Dow Jones Industrial Average had ended 0.3 per cent higher in yesterday's trade.