The Sensex at the Bombay Stock Exchange rose 66 points, or 0.4 per cent, to 18,779 in early trade, today, on sustained buying by funds and retail investors, amid positive Asian bourses. But later, in afternoon trade, the Sensex gave up almost all its initial gains, and stood just 5 points in the green, at 18,719, a short while ago.Stock markets in Japan, China, Hong Kong, Indonesia, Singapore, South Korea and Taiwan had gained between 0.1 percent and 1.3 percent, today, after some surprisingly strong US economic data and corporate earnings gave investors reason for optimism about the US economy. The US Dow Jones Industrial Average had ended 0.7 per cent higher in yesterday's trade.