The Sensex at the Bombay Stock Exchange gave up all its initial gains, to stand 6 points in the negative zone, at 18,433, on profit-booking, in afternoon deals, a short while ago. Earlier in the morning, however, the Sensex had gained 144 points, to 18,583, amid easing crude oil prices. The key stock indices in Japan, Hong Kong, South Korea, China, Taiwan and Singapore were trading mixed, on Wednesday. The US Dow Jones Industrial Average had ended 1 per cent higher in on Tuesday's trade.