Elon Musk has urged leading AI laboratories and Chinese companies to run checks on other labs' systems. He delivered that message while some in tech are asking for more caution around AI. Musk himself has major AI investments. Tesla shares dropped following the speech. Musk also was listed at the top of Forbes' annual ranking of the wealthiest Americans. He again raised the idea of combining Tesla and SpaceX. In a separate development, reports say abusive material involving children continues on X, even though Musk promised to address the problem.