The Bombay Stock Exchange benchmark Sensex gained 88 points at 20291 in the opening trade today. The Sensex was trading at 20,271, up by 67 points a short while ago. Analysts said the gain in Sensex is due to fresh buying by funds amid firm global cues. Metal and banking sector stocks are leading the rally. Meanwhile, the Hong Kong's Hang Seng index was up by 0.43 per cent, while Japanese Nikkei gained 0.93 per cent in the morning trade. The US Dow Jones Industrial Average ended 0.09 per cent higher in Tuesday's trade.