Hong Kong's Hang Seng index posted its biggest one-day gain in more than two months on Tuesday, aided by a sharp rebound in mainland stocks. The Hang Seng index rose 2.1 percent, to 19,635.81, posting its biggest percentage gain since November 12. The China Enterprises Index gained 3.0 percent, to 8,377.80 points. China stocks surged roughly 3 percent on Tuesday as weak quarterly economic data strengthened market expectations the government will unveil more stimulus moves.