Arc enables Bitcoin liquidity with cirBTC in its stablecoin ecosystem

Circle has brought Bitcoin-backed collateral into a regulated, stablecoin-native blockchain environment without asking BTC holders to sell a single satoshi.

Circle Wrapped Bitcoin, branded cirBTC, went live on the Arc network on September 21, 2026, five days after Arc itself launched its mainnet. The token offers 1:1 backing by actual Bitcoin, meaning every cirBTC in circulation is matched by a real BTC held in reserve.

What cirBTC actually does

Circle International Bermuda Limited issues cirBTC, and the Bermuda Monetary Authority regulates the operation. Real-time proof of reserves runs through Chainlink’s on-chain verification system.

Users can convert from BTC, cbBTC, or wBTC into cirBTC with no fees on select flows, accessing the token through Arc’s native portal for swaps and bridges, or through Circle Mint for institutional participants. Circle Mint now also includes a Digital Asset-Backed Borrowing option for qualifying institutions. The infrastructure underneath cirBTC shares the same plumbing as USDC and EURC.

The numbers from day one

Morpho, one of the first lending protocols to integrate cirBTC, reported more than $150M in deposits into its USDC and EURC vaults on the first day, with cirBTC serving as the collateral layer. Aave V4 also moved quickly, opening cirBTC, USDC, and EURC markets on Arc almost simultaneously.

As of September 19 to 20, 2026, total cirBTC supply stood at roughly 949 tokens, with approximately 379 to 397 of those residing on the Arc network and the remainder on Ethereum. At the time, that supply was valued at around $77M. Reserves exceeded the token count, sitting at approximately 951 BTC.

Arc’s Layer-1 blockchain uses USDC as both its gas token and its primary settlement asset, making it structurally different from chains where ETH or a native governance token handles those functions.

Why this particular wrapped Bitcoin matters

Circle first announced plans for cirBTC in April 2026, framing it explicitly as an alternative to existing offerings. The segregated custody model, the regulatory wrapper from Bermuda, and the Chainlink proof-of-reserves integration are all aimed at institutions that want Bitcoin exposure in DeFi but need compliance and auditability documentation.

Adding cirBTC as a collateral layer gives that audience a way to put their Bitcoin to work within Arc’s ecosystem without converting it to a dollar-denominated position first. Bitcoin becomes a productive asset rather than a static store of value within a regulated framework that Circle controls end to end.