The Sensex at the Bombay Stock Exchange gained 105 points, or 0.6 per cent, to 18.337 in opening trade on Tuesday, on emergence of selective buying by investors, amid firm regional bourses. Later, after the release of the GDP data, the Sensex jumped as much as 254 points, or 1.4 percent, to 18,486 in afternoon trade, a short while ago. Other Asian markets in Japan, China, Hong Kong, Singapore, South Korea and Taiwan were up by between 0.7 percent and 2.3 percent, on speculation that European officials will sanction more assistance for Greece.