Erasing all its intial gains, the Sensex at the Bombay Stock Exchange stood 6 points in negative territory, at 19,654 in afternoon deals, a short while ago.Earlier in the morning, however, the Sensex had opened with a good gain of 87 points, or 0.4 per cent, at 19,747, on fresh buying by funds and retail investors, amid largely firm Asian markets.Stock markets in Japan, Hong Kong, Indonesia, Singapore and Taiwan had gained between 0.1 percent and 3.8 percent, today. The US Dow Jones Industrial Average had ended 0.7 per cent higher in yesterday's trade.