In a letter dated September 2, Representative Zackary Nunn (R-Iowa) has urged Treasury Secretary Scott Bessent to have the Committee on Foreign Investment in the United States (CFIUS) review Bitmain Technologies Ltd. and Cango Inc.’s (CANG) U.S. operations, according to a Bloomberg report.
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Nunn warned that Bitmain’s mining-rig production and distribution networks could expose critical energy-grid connections and proprietary U.S. data to foreign influence.
“These companies appear to be scaling operations in the U.S. through complex ownership structures and financing arrangements that may not be fully transparent to regulators or the public,” the letter states.
Bitmain, the world’s largest bitcoin-mining machine maker, commands an estimated 80% of the Bitcoin mining manufacturing market. The company began reshoring to the U.S. in late 2024 to sidestep tariff barriers, setting up a Texas facility that now assembles its flagship Antminer series. While this shift has alleviated trade tensions, it has also stoked unease among lawmakers about supply-chain security.
Cango, though younger, has similarly expanded its American presence. The firm is now a top five Bitcoin miner by hashrate, after exercising multiple trade agreements with Bitmain in late 2024 and early 2025.
Read More: Cango mines 1,404 Bitcoin in Q2 and shifts to USD reporting after $352 million China divestiture
CFIUS, an interagency panel led by the Treasury Department and including Defense, State, Commerce, and Homeland Security, reviews foreign investments for national security implications. Its remit covers mergers, acquisitions, and infrastructure projects that could transfer control of sensitive technology or critical systems to foreign entities.
The lawmaker’s request could prompt CFIUS to open preliminary reviews, which may result in mitigation agreements or even a formal prohibition if national security risks are deemed too great. Both companies have yet to comment on the developments.
Cango recently completed a $352 million divestiture from China and has elected to report future accounts in U.S. dollars instead of Chinese renminbi.
