PANews reported on November 21 that, according to Bloomberg, citing sources familiar with the matter, Bitcoin mining hardware maker Bitmain is under investigation for several months to assess whether its products pose a risk to U.S. national security. The investigation, codenamed "Operation Red Sunset," is being led by the U.S. Department of Homeland Security. Specifically, it focuses on assessing whether the company's machines could be remotely controlled for espionage or used to disrupt the U.S. power grid. During the investigation, not only were the chips and firmware of Bitmain machines docked at U.S. ports examined, but investigators also reviewed potential tariff and import tax violations.

Bitmain responded that it "strictly complies with U.S. and applicable laws and regulations and has never engaged in any activities that pose a risk to U.S. national security," and stated that claims regarding its ability to remotely control devices are "absolutely unfounded." The company added that it is unaware of any investigation called "Operation Red Sunset" or any investigations concerning tariffs and other import duties, and attributed past device seizures to routine inspections by the Federal Communications Commission, stating that "no abnormalities were found."