Giving up all its initial gains, the Sensex at the Bombay Stock Exchange stood 23 points, or 0.1 per cent in negative territory, at 18,555 in afternoon deals, a short while ago. Earlier in the morning, however, the Sensex had opened with a gain of 98 points, or 0.5 per cent, at 18,676, on fresh buying by funds and retail investors, amid firm regional markets. Key stock indices in Japan, China, Hong Kong, Indonesia, Singapore and South Korea were up by between 0.2 percent and 1.2 percent, today. The US Dow Jones Industrial Average had ended 1 per cent higher in yesterday's trade.