HONG KONG — China’s Internet companies, in recent years, have been the shining stars of growth, with Alibaba and Tencent rivaling in size some of their most formidable global competitors. Inspired by their success and driven by huge buyouts of smaller companies by China’s Internet giants, investors have poured money into new start-ups. But new figures from the end of 2015 show that wave of investment may be coming to an end, or at least slowing. In China, venture capital investment fueling the growth of new start-ups fell 29 percent in the fourth quarter from the level in the third...