President Donald Trump has blocked a business deal involving U.S. photonics company HieFo Corp and New Jersey-based aerospace and defence firm Emcore, citing national security concerns and links to China.

The decision was announced through a White House order released on Friday. The order stops HieFo Corp from acquiring assets of Emcore in a deal valued at nearly $3 million. According to the order, the president believes the transaction could pose a threat to the national security of the United States.

In the official order, Trump stated that HieFo Corp is “controlled by a citizen of the People’s Republic of China.” He further said that the company’s 2024 acquisition of Emcore’s businesses led him to believe that HieFo “may take action that threatens to impair the national security of the United States.”

The order did not identify the individual alleged to control HieFo, nor did it provide specific details about the security concerns behind the decision. However, the president made his stance clear by formally blocking the deal.

“The Transaction is hereby prohibited,” Trump said in the order. He also directed HieFo Corp to “divest all interests and rights in the Emcore Assets, wherever located,” within a period of 180 days.

Following the president’s decision, the U.S. Treasury Department issued a statement confirming that the Committee on Foreign Investment in the United States (CFIUS) had identified a national security risk during its investigation of the deal. However, the statement did not explain what the risk was.

“The Committee on Foreign Investment in the United States identified a national security risk,” the Treasury Department said after the order was issued.

CFIUS is a U.S. government body responsible for reviewing foreign investments to determine whether they could threaten national security. Its findings often play a key role in presidential decisions related to foreign acquisitions.

As of late Friday, neither HieFo Corp nor Emcore had responded publicly to the announcement. Neither companies could be immediately reached for comments, and no statements had been posted on their official websites.

At the time of the transaction, Emcore was a publicly traded company, though it was later taken private. Emcore has previously stated that HieFo purchased its chips business and its indium-phosphide wafer-fabrication operations for $2.92 million.

HieFo Corp had earlier said that it was co-founded by Genzao Zhang and Harry Moore. Zhang is a former vice president of engineering at Emcore, while Moore’s LinkedIn profile describes him as a former senior sales director at the same company.

The White House order adds to ongoing scrutiny by the U.S. government over foreign involvement in sensitive sectors such as aerospace, defence, and semiconductor manufacturing. These industries are considered critical to national security due to their role in military, communications, and advanced technology systems.

Although the order does not provide further details, it makes clear that the administration views the transaction as a potential risk. By requiring HieFo to divest the assets within six months, the government has effectively reversed the deal.

For now, the future of the Emcore assets remains uncertain as the divestment process begins. Neither company has clarified what steps they will take next following the president’s directive.

The decision reflects the administration’s continued focus on restricting transactions that involve sensitive technology and foreign control, especially where links to China are concerned.