China will impose a cybersecurity review on mainland companies seeking initial public offerings in Hong Kong on national security grounds, according to a draft regulation released on Sunday, adding a new layer of oversight for Chinese tech giants from ByteDance to Didi Chuxing if they choose to sell shares in the city. The Cyberspace Administration of China (CAC), the country’s top cybersecurity authority, released the draft regulation titled “Network Data Security Management Regulations” for public consultation through December 13, with the final version being subject to change. The regulation stipulates that “data-processing entities seeking a listing in Hong Kong that…