The U.S. Securities and Exchange Commission has issued a subpoena to controversial Riot Blockchain, a company that has been in the news more often than it would wish. The Castle Rock, Colorado-based company made the disclosure in its annual report in which it listed internet retailer Overstock as one of its biggest competitors. The subpoena was not a big surprise to many, given the SEC’s promise early this year that it would investigate companies that had switched to crypto-related activities in recent times to take advantage of the heightened investor interest in the industry. Riot To Fully Cooperate With SEC RiotPowered by WPeMatico