Circle Internet Group launched the public mainnet of Arc, its USDC-native Layer-1 blockchain, on Wednesday, with a founding validator cohort that includes BlackRock, DTCC, Visa and Mastercard.
The launch follows a period operating a private mainnet with over 100 institutional and ecosystem builders, giving Circle an extended testing phase before opening the network to the public.
FOUNDING VALIDATORS SPAN FINANCE AND PAYMENTS
Alongside Circle, the founding validator cohort includes BlackRock, DTCC, Galaxy, Global Payments, ICE, Mastercard, MoneyGram, SBI Group, Standard Chartered, Sumitomo Corporation and Visa. The breadth of the cohort, spanning asset management, market infrastructure, payments and banking, reflects the scale of institutional backing Circle has assembled for the network ahead of its public launch.
Arc's native gas token is USDC itself, and the network offers sub-second deterministic transaction finality of approximately 350 milliseconds through its Malachite consensus engine, a design intended to make the blockchain suitable for stablecoin-based financial applications requiring rapid settlement.
LAUNCH FOLLOWS EARLIER TOKEN PRESALE
Circle first announced the founding validator cohort and the 16 September mainnet target on 5 August 2026, alongside its second-quarter 2026 earnings. An ARC token presale held on 11 May 2026 raised $222 million at a $3 billion fully diluted valuation, led by a16z crypto with a $75 million commitment.
BlackRock is expected to deploy its BUIDL fund on Arc at or shortly after launch, and Circle is collaborating with DTCC on tokenising DTC-custodied assets on the network, pointing to concrete institutional use cases planned for the platform as it moves from private testing into full public operation.
The 11 May 2026 presale, which raised $222 million at a $3 billion fully diluted valuation led by a16z crypto's $75 million commitment, gave Circle early capital and investor validation well ahead of Wednesday's public mainnet launch. The gap of more than four months between the presale and the public launch allowed Circle to run its private mainnet with the more than 100 institutional and ecosystem builders that helped shape the network before it opened more broadly.
With founding validators spanning global custody, payments, market infrastructure and traditional banking, Arc's launch represents one of the more heavily institutionally backed public blockchain networks to date, reflecting the extent to which large financial institutions have engaged directly with Circle in building out the infrastructure ahead of the public mainnet going live.
The approximately 350-millisecond finality delivered by Arc's Malachite consensus engine, combined with USDC serving as the network's native gas token, positions the blockchain specifically for stablecoin-denominated settlement use cases rather than as a general-purpose smart contract platform, distinguishing Arc's design focus from many existing public blockchains.
Circle's decision to run a private mainnet phase with more than 100 institutional and ecosystem builders ahead of Wednesday's public launch gave the company an opportunity to refine the network's performance and validator coordination before opening Arc to the wider public, a staged rollout approach consistent with the scale of institutional participation the project has attracted.
Circle's 5 August 2026 announcement of the founding validator cohort and the 16 September mainnet target, made alongside its second-quarter 2026 earnings, gave the market more than six weeks' advance notice of the launch date, allowing validators and prospective users time to prepare ahead of the network going live.