Chinese companies hoping to sell their shares in the United States must start making more disclosures about their potential risks before U.S. regulators will allow them to list their stock. The Securities and Exchange Commission announced the move Friday after Beijing said it would step up its supervision of Chinese companies listed overseas, including reviews of their cybersecurity. SEC Chair Gary Gensler pointed in particular to Chinese businesses that use shell companies to get around Chinese rules blocking foreign ownership for their industries. Under these deals, the Chinese business forms a shell company in the Cayman Islands or somewhere else....