Sensex soared by over 129 points at 20,234 level in the opening trade today. Later it shed its initial gains and was trading at 20,073, down by over 30 points a short while ago. Analysts said the fall in Sensex is due to profit booking ahead of the expiry of derivatives contracts for the September month. Meanwhile, the Hong Kong's Hang Seng index was up by 1.02 per cent, while Japanese Nikkei gained 0.38 per cent in the morning trade. The US Dow Jones Industrial Average ended 0.43 per cent higher in Tuesday's trade