Circle launched Arc, a Layer-1 blockchain for stablecoins and AI agents, and will present its regulated infrastructure to financial institutions at Sibos 2026 in Miami from September 28 through October 1. Arc uses USDC as its native gas and settlement asset, delivers sub-second deterministic finality through Circle's Malachite consensus engine and counts BlackRock, Visa and Mastercard among its launch validators. Circle's Agent Stack supports autonomous software through provenance proofs, reputation systems and nanopayments. Five days after Arc's September 16 mainnet launch, Circle International Bermuda Limited launched cirBTC, a 1:1 Bitcoin-backed token whose segregated reserves are held by Circle National Trust and monitored through Chainlink Proof of Reserve. Eligible Circle Mint customers can use cirBTC as collateral to borrow USDC through independent third-party lending markets. Circle said USDC circulation was approximately $73 billion to $74 billion in mid-September 2026, while Sibos is expected to attract more than 10,000 attendees from over 160 countries.