The Sensex at the Bombay Stock Exchange gained 92 points, or 0.5 per cent, to 17,518, in early trade, today, on sustained capital inflows, amid firm regional bourses. But the Sensex later gave up all its initial gains, to stand 27 points, or 0.2 per cent in negative territory, at 17,399 in afternoon deals, a short while ago.Key stock indices in Japan, Indonesia, South Korea, Taiwan and Singapore were up by between 0.1 percent and 0.7 percent, today, on growing hopes that central banks across the world will take further steps to power the global economy. Over in the US, the Dow Jones Industrial Average had closed 0.6 per cent higher on Tuesday.