President Trump’s claim that China controls the Panama Canal has placed a Hong Kong tycoon and his conglomerate at the heart of a showdown between the United States and China.

That sprawling company, CK Hutchison Holdings, is one of Hong Kong’s most valuable publicly listed firms and counts some of the world’s biggest investors as shareholders. One of its subsidiaries, Hutchison Ports, has been involved in the Panama Canal since 1997.

Of Panama’s five ports, Hutchison’s are the biggest — one at each end of the canal. According to the Panama Maritime Authority, Hutchison’s ports last year served vessels carrying 39 percent of the cargo containers that passed through the canal, one of the world’s most vital waterways. (The other ports are owned by a Taiwanese company, a Singaporean company and an American-Panamanian joint venture.)

The company’s role brings to the surface unresolved questions for Washington about Beijing’s influence over Hong Kong, a special administrative region of China, which has become more pronounced in recent years. The Trump administration argues that China could use its influence over a Hong Kong company to force Panama to restrict American trade in the port.

What is CK Hutchison, and who is this tycoon?

The billionaire founder of CK Hutchison, Li Ka-shing, is a legend in Hong Kong. A high school dropout, Mr. Li, now 96, turned a small business selling plastic flowers into an empire spanning infrastructure, finance, retail and telecommunications.