Alibaba Group Holding Ltd.’s on-demand services unit is close to securing $1.2 billion of funding for expansion after getting backing from first-time investors including Silver Lake Management and China’s sovereign wealth fund, people familiar with the matter said. The latest round for Koubei, which deals in local services such as food delivery, will surpass a $1 billion target with backing from China Investment Corp., according to the people, who asked not to be named because the matter is private.