The United States Securities and Exchange Commission (SEC) has ordered crypto mining firm Marathon Digital Holdings to produce documents and communications for one of its mining facilities in Montana.

According to a Monday filing with the SEC, Marathon Digital received a subpoena regarding an investigation into possible violations of the federal securities law related to its Hardin, Montana data center. In the third quarter of 2021, the SEC ordered the mining firm to produce documents and communications for the 100-megawatt facility, for which it had made arrangements to develop and stock with Bitcoin (BTC) miners in October 2020.

Marathon Digital said it was cooperating with the SEC’s investigation but did not go into details regarding the subpoena. A separate filing from October 2020 shows the company issued 6 million shares of restricted common stock “in transactions exempt from registration.”

Share prices of Marathon Digital stock dropped roughly 17% on Monday to $63.07 as news of the subpoena reached major outlets, as did those from major crypto mining firms, including Riot Blockchain, Bitfarms, Bit Digital, and Hut 8 — falling 6%, 2%, 3%, and 5%, respectively. Though the stock prices may fall when the price of BTC drops, data from Cointelegraph Markets Pro shows the crypto asset has only dipped roughly 2.4% on Nov. 15 to reach $63,798 at the time of publication.

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Earlier on Monday, Marathon Digital announced it was planning to buy more BTC and set up new crypto miners through a $500 million private debt offering. Cointelegraph reported on Nov. 3 that the price of the company’s MARA stock reached a six-year high, with the mining firm accumulating $460 million worth of Bitcoin.