Meta CEO Mark Zuckerberg said investors must be "more worried" if he doesn't practice mixed martial arts (MMA). Zuckerberg was replying to a Threads user who shared a Meta filing which flagged "risk of serious injury and death" caused by Zuckerberg's participation in "high-risk activities". Replying to another user talking about the same topic, Zuckerberg said, "High risk=High reward."