A decision in a Russia-Ukraine trade dispute rejects an argument Trump has made to justify a 25% tariff on global auto imports.
Trade groups cited a study from the Peterson Institute for International Economics that found 195,000 U.S. jobs could be lost if the tariffs were imposed.
The SEC says its review left "unresolved questions" about the source of funds for the deal and the ownership structure.
The demise of $1.2 billion deal suggests U.S. officials are concerned about the data security implications of takeovers by Chinese investors.
The decision, which cited national security concerns, may signal problems for other Chinese deals under review by the administration.
Many companies are aware of cyber threats, but preventing attacks takes more than having the right firewalls and software.
