At a time when deals between American and Chinese companies are on the rocks, an early example that united a major Wall Street deal maker with the Chinese government has come to an end.

China Investment Corporation, China’s sovereign wealth fund, has sold its stake in Blackstone Group, the American private equity giant, the latter said in a recent filing. The fund, known as C.I.C., did not disclose a reason for the sale, and neither side disclosed how big it was.

The sale ends an 11-year investment that seemed to presage a new era of economic relations between the two countries. It helped Stephen Schwarzman, Blackstone’s co-founder, become a major player in business and diplomatic circles between the two countries.

That era seems very much over.

American officials have taken a harder stance against Chinese money as Chinese buyers have looked to strike deals in sensitive areas like semiconductors and self-driving cars. President Trump’s criticism of China’s trade policies and his new tariffs on imports of steel and aluminum have worsened relations between Washington and Beijing. The souring atmosphere could put Mr. Schwarzman, who serves as an informal economic adviser to Mr. Trump, in a difficult position.