Circle Launches cirBTC: 1:1 BTC-Backed Token on Ethereum

Circle launches cirBTC on Ethereum with onchain reserve verification

Circle has officially launched cirBTC on Ethereum, a wrapped Bitcoin token fully backed 1:1 by native BTC held in regulated custody. The new token integrates Chainlink Proof of Reserve to offer continuous onchain verification of custody holdings, aiming to deliver transparent Bitcoin-backed collateral to institutional DeFi markets.

What cirBTC is and who it targets

Built for institutional users active in lending, market making, treasury operations, over-the-counter trading, and settlement, cirBTC lets organizations mobilize Bitcoin liquidity into Ethereum-based smart contracts without selling their underlying BTC. According to Circle, each cirBTC token corresponds to an equivalent quantity of native Bitcoin segregated in custody by a regulated Circle entity and kept separate from Circle's corporate assets.

By enabling Bitcoin to remain in custody while a tokenized equivalent circulates through DeFi protocols, cirBTC is intended to act as a neutral collateral instrument that institutions can deploy across lending markets, automated market makers, and tokenized trading workflows.

Onchain reserve transparency with Chainlink

Circle added Chainlink Proof of Reserve to provide public, cryptographic checks on cirBTC backing. This integration enables counterparties, exchanges, and risk teams to verify reserve balances and custody addresses on the Bitcoin blockchain, increasing real-time visibility into the token's backing and reducing counterparty risk when the token is used as collateral.

How cirBTC fits into Circle's ecosystem

The token can be minted and redeemed via Circle Mint, Circle's institutional liquidity platform. Combining cirBTC with USDC enables workflows where Bitcoin-backed collateral and dollar liquidity operate side by side, streamlining treasury, margining, and settlement processes for institutional counterparties.

Ethereum was chosen as the initial launch network because much of institutional DeFi, tokenization activity, and liquidity provisioning already happens there. Circle has also signaled a multichain strategy: cirBTC is expected to expand to additional chains through Arc, Circle's layer-1 infrastructure, in order to extend access to wrapped Bitcoin collateral across interoperable environments while preserving the same custody and proof-of-reserve standards.

Market context and differentiation

The wrapped Bitcoin market already includes established players such as BitGo Wrapped Bitcoin, Coinbase Wrapped Bitcoin, Kraken Wrapped BTC, Binance Wrapped BTC, and others. Circle noted these incumbents serve large portions of the market, with some competing wrapped BTC products reaching multi-billion-dollar market capitalizations.

Circle emphasizes that its business model differs from some competitors because it does not operate a centralized exchange, decentralized exchange, or a lending protocol. That positioning is presented as a way to minimize conflicts of interest, enabling institutions to use cirBTC across multiple trading venues and client relationships without concerns about issuer-driven competition for liquidity.

Implications for institutional DeFi and custody

For institutional treasurers and market makers, cirBTC expands the toolbox for collateral management: Bitcoin owners can retain custody of native BTC while leveraging tokenized exposure in smart contract lending, decentralized trading, and automated liquidity strategies. The addition of Chainlink Proof of Reserve addresses one of the main frictions for institutions considering wrapped assets: verifiable, continuous proof that onchain tokens are fully backed by offchain reserves.

Looking ahead, Circle's plan to bring cirBTC to Arc and other chains signals an intent to make Bitcoin-backed collateral broadly composable across diverse blockchain ecosystems, supporting cross-chain settlement and institutional liquidity needs under consistent custody and auditability standards.

Overall, cirBTC aims to combine Circle's institutional custody controls, transparent reserve reporting, and mint-and-redeem plumbing to offer a neutral, auditable wrapped Bitcoin product designed for professional participants in the evolving decentralized finance landscape.