The Sensex at the Bombay Stock Exchange gave up all its initial gains, to stand 51 points, or 0.2 percent in negative territory, at 21,050 in afternoon trade, a short while ago. Earlier in the morning, however, the Sensex had advanced 56 points, or 0.3 percent, to 21,157, on continued buying by funds. The 30-share Sensex had gained over 390 points in the previous two trading sessions. Stock markets in Japan, China and South Korea had gained about 0.2 percent, each, today. The US Dow Jones Industrial Average had climbed 0.5 per cent to close at another record high in yesterday's trade.