The Bombay Stock Exchange benchmark Sensex today recovered by over 87 points to open at 19,959 in the morning trade. The Sensex was trading at 19,986, up by over 114 points when reports last came in. Analysts said the gain in Sensex is due to fresh buying by funds and retail investors amid a firming trend overseas. Meanwhile, in Asian markets, the Hong Kong's Hang Seng Index was up by 0.68 per cent, while Japanese Nikkei gained 0.66 per cent in the morning trade today. In the US, the Dow Jones Industrial Index ended 1.18 per cent up yesterday.