The US Securities and Exchange Commission (SEC) has concluded its three-year investigation into Hiro Systems, the developer of Bitcoin’s Stacks layer-2 blockchain. The probe was initiated after Hiro, formerly known as Blockstack, raised $70 million from token sales between 2017 and 2019. The company began treating its native token, STX, as a security under US law since its 2018 launch. However, Hiro argued in 2021 that the Stacks blockchain had become sufficiently decentralized, negating its status as a securities issuer. This marks the second crypto-related investigation the SEC has dropped this week.