The Bombay Stock Exchange benchmark Sensex opened about 147 points higher at 18,367 on Monday. Sensex was trading at 18382, up by over 161 points when reports last came in. The broad-based National Stock Exchange index, Nifty also gained 41 points to trade at 5,521 points. Meanwhile, Hong Kong's Hang Seng index was up by 1.23 per cent, while the Japanese Nikkei gained 1.31 per cent in the morning trade on Monday. The US Dow Jones Industrial average ended 1.24 per cent higher in the previous session on Friday.