GOP Lawmaker Seeks Reviews of Two Bitcoin Mining Machine Makers

A Republican lawmaker has called for a federal review of two companies that manufacture Bitcoin mining hardware, saying that their increasing presence in the US could present a national security risk, according to a letter reviewed by Bloomberg News.

One of the companies is Bitmain Technologies Ltd., a China-based firm that is the world’s leading manufacturer of cryptocurrency mining machines. The other, Cango Inc., is a potential acquisition target for Bitmain, Representative Zachary Nunn of Iowa wrote.

Nunn, a member of the House Select Committee on the Chinese Communist Party, sent the letter on Sept. 2 to US Treasury ...