Treasury Pressured to Scrutinize Opaque Ties in Bitcoin Mining Empire

Representative Zachary Nunn of Iowa has requested that the U.S. Treasury conduct a national security review of two Chinese firms operating in the Bitcoin mining industry, Bitmain Technologies Ltd. and Cango Inc. In a letter dated September 2, Nunn cited concerns over the opaque ownership structures of both companies and potential links to foreign state actors. The request was directed to Treasury Secretary Scott Bessent and called for an investigation by the Committee on Foreign Investment in the United States (CFIUS) .

Bitmain, headquartered in Beijing, dominates the global Bitcoin mining hardware market, with a reported 80% market share based on a University of Cambridge report. The company is a key supplier of mining machines and has been increasingly active in the U.S. market. Nunn emphasized that the firm’s expansion in the U.S. is occurring through complex ownership structures and financing arrangements that may not be fully transparent to regulators or the public .

Cango, a Nasdaq-listed company based in China, has also drawn scrutiny due to its potential connection with Bitmain. Although Cango has not publicly confirmed any acquisition by Bitmain, the firm has been linked to the larger Bitcoin mining ecosystem. Nunn raised concerns about Cango’s energy consumption and its possible affiliations with foreign governments, which could pose national security risks. These concerns align with broader worries about the use of foreign-made chips in surveillance-related activities .

The request for a CFIUS review follows recent high-profile actions by the committee, including its role in the TikTok investigation and the blocked acquisition of Grindr by a Chinese firm. Last year, CFIUS also played a key role in President Biden’s decision to prohibit a Bitcoin mining facility near a strategic Air Force base in Wyoming due to surveillance concerns. Nunn’s letter underscores the growing interest among U.S. lawmakers in scrutinizing foreign investments in the U.S. tech and energy sectors .

Nunn, who serves on the House Select Committee on the Chinese Communist Party, has previously focused on assessing Beijing’s influence across various sectors. In his letter to Bessent, he pointed to Bitmain’s recent activities, including a $300 million order of mining machines by American Bitcoin Corp—a mining firm backed by Eric Trump. Bitmain has since clarified that it is not pursuing ownership of U.S. power infrastructure, addressing reports of its potential expansion into energy markets .

Both Bitmain and Cango have denied any connections to government entities and asserted compliance with U.S. law. However, the lack of transparency in their operations and the potential for national security risks remain central to Nunn’s concerns. The call for a CFIUS review highlights the increasing scrutiny of foreign entities in the U.S. crypto and energy sectors, particularly those with ties to China .