IDG Capital has backed some of China’s hottest startups. The venture capital and private equity firm that got its start in China in 1993 has made more than 1,000 investments over the past two decades. It made early bets on the Chinese search engine giant Baidu and the powerhouse social networking and gaming giant Tencent but has also backed Xiaomi, SenseTime, Pony.ai and Pinduoduo. Today, it has over $23 billion in assets under management, according to PitchBook.  It has stayed ahead of the curve to become the world’s fourth-most successful investor in unicorns, according to a Hurun report.Unicorns are privately held companies worth $1 billion or more.  Though IDG Capital was formed in the United States, its portfolio is predominantly Chinese.Data from PitchBook shows that 608 of the 732 companies it’s backed are Chinese, as of March 5. Far behind is second-place United States with 72 companies. Patrick J. McGovern, the late chairman of the Boston-based parent co