Stablecoin issuer Circle (CRCL) has communicated in its latest earnings call that its blockchain operating system Arc Mainnet will be launched next month on Sept. 16. The operator of the world's second-largest stablecoin, USDC, also revealed that it has entered into partnerships regarding Arc Mainnet, key among them being with the Depository Trust & Clearing Corporation (DTCC) and the world's largest asset manager, BlackRock (BLK).