Circle has launched cirBTC, a new wrapped Bitcoin token on Ethereum designed to bring native Bitcoin liquidity into decentralized finance (DeFi) while offering greater transparency around its reserves and custody arrangements.

According to Circle's Sept. 4, 2026 announcement, each cirBTC token is backed on a one-to-one basis by native Bitcoin. The product uses segregated custody and on-chain reserve verification through Chainlink Proof of Reserve, giving users and institutions a way to monitor the assets supporting tokens in circulation.

cirBTC Brings Bitcoin Into Ethereum DeFi

Wrapped Bitcoin products allow Bitcoin holders to use their assets within blockchain networks that support smart contracts. Because native Bitcoin cannot directly operate on Ethereum's programmable infrastructure, tokenized versions can provide access to lending, collateral, and trading applications without requiring holders to sell their underlying BTC.

The launch comes as Bitcoin remains the largest digital asset by market value. With the Bitcoin market valued at about $1.60 trillion and BTC trading around $79,640, efforts to connect Bitcoin liquidity with Ethereum-based financial applications could have significant implications for the broader DeFi market. Wrapped Bitcoin already represents one of the largest collateral assets in Ethereum DeFi, with WBTC alone long serving as the dominant form of Bitcoin liquidity on the network.

Circle is positioning cirBTC as an institution-focused wrapped Bitcoin product, combining one-to-one native BTC backing with segregated custody and independent onchain reserve verification. Unlike some existing wrapped Bitcoin products, including WBTC and tBTC, cirBTC places particular emphasis on how reserves are held and verified. Notably, Coinbase launched its own wrapped Bitcoin product, cbBTC, in September 2024, signaling that major regulated crypto firms see institution-grade tokenized Bitcoin as a growing market segment.

The underlying Bitcoin is held in segregated accounts at Circle National Trust, a federally regulated custodian. Circle said the reserves are legally and operationally separated from its corporate assets. The structure is intended to reduce concerns related to commingled funds and counterparty exposure, two issues that can affect confidence in tokenized assets.

Chainlink Provides Reserve Verification

Circle is using Chainlink's decentralized oracle infrastructure to make reserve information available onchain. Market participants, including DeFi protocols and asset managers, can use disclosed Bitcoin wallet addresses to independently examine the reserves backing cirBTC.

The approach is designed to make the relationship between circulating tokens and underlying Bitcoin more observable. This could be particularly relevant to lending platforms and risk managers who need reliable collateral information when calculating exposure, setting borrowing parameters, and managing liquidity. Rather than relying solely on statements from the token issuer, users can examine blockchain-based reserve information as part of their assessment of the product.

Arc Integration Planned

cirBTC is currently available on Ethereum, but Circle plans to extend the token to Arc, its upcoming Layer 1 blockchain, following the network's mainnet launch. The planned Arc integration would bring cirBTC into Circle's broader blockchain infrastructure and potentially allow Bitcoin liquidity to move between Ethereum-based DeFi applications and Arc-based financial services. Circle also expects to pursue additional blockchain integrations as demand and liquidity develop.

The planned expansion could make cirBTC a key component of Circle's broader infrastructure by connecting Bitcoin liquidity with Ethereum, Arc, and potentially other blockchain ecosystems.

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Aave Adoption Could Be a Key Test

Major DeFi platforms have already shown interest in the product. Aave governance discussed potential integration of cirBTC with its V3 and V4 Core systems on Ethereum in July, according to the report.

Integration with Aave and similar protocols could expand cirBTC's practical use. In combination with USDC, Circle's dollar-pegged stablecoin, users could potentially borrow USDC against Bitcoin collateral or use the assets in trading and settlement strategies across blockchain networks.

The launch comes as institutions increasingly seek digital-asset infrastructure that offers greater transparency and controls. Wrapped Bitcoin products have historically faced scrutiny over reserve practices, custody arrangements, and governance structures — scrutiny that intensified in 2024 when WBTC's custodian BitGo announced a joint-venture arrangement involving BiT Global and Justin Sun, prompting several DeFi protocols to re-evaluate or cap their WBTC exposure. Circle's model attempts to address those concerns through regulated custody, asset segregation, and blockchain-based verification.

If major DeFi protocols and institutional participants adopt cirBTC, the product could strengthen the role of verifiable, Bitcoin-backed assets in Ethereum-based financial markets. Adoption will ultimately determine whether cirBTC can establish itself in the competitive wrapped Bitcoin sector. Its ability to maintain transparent reserves while attracting liquidity, market makers, asset managers, and major DeFi protocols will be closely watched as Circle expands the product beyond Ethereum.