Circle Sets Sept. 16 Public Mainnet Date for Arc Blockchain as BlackRock, Visa Join Validator Network

Circle is preparing to open the public mainnet for Arc, its institutional layer-1 blockchain, on Sept. 16, 2026, marking a significant structural pivot toward specialized settlement rails built exclusively around fiat-backed stablecoins.

The launch follows the assembly of a founding validator cohort comprising Wall Street and payment industry heavyweights, including BlackRock, DTCC, Visa, Mastercard, Intercontinental Exchange (ICE), Global Payments, MoneyGram, Standard Chartered, SBI Group, Sumitomo Corporation, and Galaxy, operating alongside Circle.

Ahead of the public deployment, Arc’s private mainnet already hosts more than 100 institutional and ecosystem builders. Circle CEO Jeremy Allaire disclosed in August 2026 that the network’s public testnet, active since October 2025, had processed over 500 million transactions across nearly 3 million wallets.

The scale of institutional backing was signaled in May 2026, when Circle closed a $222 million presale for Arc’s native ARC token at a $3 billion fully diluted valuation. The round was led by Andreessen Horowitz with a $75 million commitment, with additional participation from BlackRock and Apollo Funds. Recognized revenue from the token presale prompted Circle to nearly double its full-year 2026 guidance for “other revenue” to between $310 million and $330 million, up from a previous target of $150 million to $170 million.

The push into dedicated blockchain architecture addresses long-standing limitations in general-purpose networks, where gas price spikes, probabilistic settlement, and public transaction visibility have hampered corporate adoption.

“We’ve helped enterprises and builders use USDC across dozens of networks,” Rachel Mayer, VP of Product Management at Circle, told Decrypt. “The consistent feedback has been: make costs predictable, settlement finality deterministic, and privacy compatible with real-world obligations.”

To remove fee volatility, Arc utilizes USDC as its native gas token, supported by a paymaster framework that allows transactions to be settled in alternative stablecoins. Built on Ethereum’s EIP-1559 model, the network smooths transaction costs through a weighted moving average of demand, routing captured fees directly to an on-chain Arc Treasury.

“Arc’s fast finality and native gas coupled with Circle’s CCTP and Gateway interoperability service-as-a-stablecoin liquidity hub, enable USDC to move across the blockchain ecosystem freely,” Mayer said. “So builders and users can be on the networks that fit their needs while still tapping Arc’s stablecoin-optimized rails.”

Consensus on Arc is executed through Malachite, a Byzantine Fault Tolerant engine derived from Tendermint, supporting deterministic finality while moving toward a permissioned Proof-of-Stake model. Day-one integrations include decentralized finance protocols Aave, Morpho, and Uniswap, alongside custody and access infrastructure from Binance Wallet, Chainlink, Fireblocks, Kraken, Ledger, MetaMask, and Upbit. Payment processing will be handled by Rain, Thunes, and Wirex.

Asset managers are already positioning core products on the chain. BlackRock is scheduled to deploy its tokenized money market fund, BUIDL, directly on Arc at launch. The Depository Trust & Clearing Corporation (DTCC) plans to enable tokenization of custodial assets on the network during the second half of 2027.

For enterprise compliance, Arc embeds modular privacy tools, beginning with confidential transfers that mask transaction amounts using Trusted Execution Environments while keeping wallet addresses visible. Institutions can grant selective view keys to auditors and regulators. The roadmap incorporates zero-knowledge proofs, multi-party computation, and fully homomorphic encryption, complemented by Circle’s Mint, Cross-Chain Transfer Protocol (CCTP), and Gateway tools.

“Arc strengthens the broader multichain ecosystem by unlocking new use cases, partners, and institutional liquidity on-chain,” Mayer said. “Builders and users can be on the networks that fit their needs while still tapping Arc’s stablecoin-optimized rails.”

The network’s economic structure relies on the ARC token, outlined in Circle’s May 2026 white paper as a coordination asset for validator consensus and protocol governance. ARC starts with an initial supply of 10 billion tokens, carrying an annual issuance rate of 2% to 3% aimed at achieving inflation neutrality over time. Token distribution reserves 60% for ecosystem growth and developer grants, 25% for Circle, and 15% for a long-term contingency reserve. ARC stakers receive discounted transaction rates and preferential access to Circle services.

Institutional velocity around stablecoin rails follows legislative shifts in the U.S., notably the passage of the GENIUS Act signed by President Donald Trump in July 2025, which provided clearer ground rules for dollar-backed digital assets.

“Regulatory clarity is often a catalyst for institutional adoption,” Mayer said, adding that Arc is designed to be “enterprise-grade.”