NEW YORK – When SpaceX starts trading this week, one group will be noticeably absent from the frenzy: investors from China and Hong Kong. They are also likely to miss out on the upcoming initial public offering (IPO) for OpenAI.SpaceX, Elon Musk’s rocket maker and artificial intelligence company, has excluded investors in China and Hong Kong from participating in its IPO, according to five people with knowledge of the decision.OpenAI, another leading AI company, is likely to impose the same restriction when it goes public in 2026, said three people with knowledge of the discussion. The company has already barred...