Tighter controls on Chinese investment in the US threaten to make the flow of private capital between the countries more of a one-way street.

President Trump this week signed into law a reform of the Committee on Foreign Investment in the US, which advises the president on when to block foreign deals on national-security grounds. The overhaul gives CFIUS greater power to restrict investments by venture capital and private equity firms —presenting a potential barrier to investment flows that have surged this year.