Hesai Group, a Shanghai-based maker of laser sensors used for next-generation vehicles, celebrated a Nasdaq stock offering in February that was heralded by some as a comeback for Chinese listings in the U.S.

Less than nine months later, Hesai has become an example of how the U.S.-China battle over technology is roiling the business world. Its stock is down more than 50%, and the company is on the back foot, hiring lobbyists and defending its reputation.