Chinese crypto mining rig maker Canaan (CAN) on Thursday morning disclosed it has come under the gaze of the U.S. Securities and Exchange Commission (SEC) for its ties to Beijing.

At issue, according to the SEC, is Canaan's use of an auditor for its 2021 annual report that the U.S. Public Company Accounting Oversight Board (PCAOB) could not fully inspect or investigate.

Canaan has until May 25 to file documentation with the SEC to prove that it is not "owned or controlled" by a foreign government.

Canaan is one of over 70 companies so-identified yesterday, with other names including electric vehicle makers XPeng and Nio, e-commerce giants JD.com and Trip.com, and the maker of one of China's COVID-19 vaccines, Sinovac Biotech.

China-linked crypto mining-related stocks are also headed sharply lower, with Canaan (CAN), Ebang (EBON), Bit Digital (BTBT) and Bit Mining (BTCM) all off 6%-10%.