Circle has launched cirBTC, a wrapped bitcoin token live on Ethereum and backed 1:1 by native BTC held in segregated custody, with reserve levels published on-chain through Chainlink Proof of Reserve. The product targets institutions that want bitcoin as programmable collateral without selling the underlying position, and it puts Circle, the issuer of USDC, in direct competition with established wrapped-btc issuers such as BitGo and the WBTC joint venture.
How the reserve model works
Every cirBTC token is backed by native bitcoin held for the exclusive benefit of token holders. The BTC sits with Circle’s Bermuda affiliate and is safeguarded by Circle National Trust, a federally chartered trust bank supervised by the Office of the Comptroller of the Currency. Circle says those reserve accounts are legally and operationally separate from its corporate balance sheet, a structure designed to keep customer collateral out of reach of the company’s own creditors.
Verification runs on three observable data points. First, the native BTC held in disclosed reserve addresses, which anyone can check on a Bitcoin block explorer at any time. Second, the on-chain reserve value that Chainlink’s oracle network independently verifies and publishes for smart contracts to read. Third, the cirBTC supply issued across supported blockchains, visible in the token contract itself. When tokens are redeemed, the supply shrinks and the corresponding BTC is released through the redemption process, so cirBTC in circulation should never exceed the reserve.
Chainlink’s infrastructure turns that into a machine-readable feed. Protocols and risk systems can monitor the reserve ratio continuously rather than relying on periodic attestations, the format most wrapped-asset issuers have used until now. For a lending market deciding whether to accept a wrapped asset as collateral, a live feed is materially different from a monthly PDF.
Why wrapped bitcoin matters to institutions
Native bitcoin cannot interact with smart contracts. It has no mechanism to enter the lending pools, trading venues and settlement systems that run on Ethereum and other programmable networks. Wrapped tokens solve that by holding BTC in custody and issuing a corresponding token elsewhere, letting the position work as collateral without being sold. A desk that wants yield on its bitcoin has historically had to choose between selling into stablecoins or trusting one of a handful of wrapped issuers with mixed transparency records.
Circle frames cirBTC as an institutional-grade standard aimed at OTC desks, market makers and DeFi protocols. The token integrates with Circle Mint and USDC, so a desk can move between dollar liquidity and bitcoin collateral inside one stack. Aave has discussed a potential integration on Ethereum, which would allow borrowing against bitcoin collateral and trading strategies pairing cirBTC with USDC. The company also pitches the token as neutral infrastructure, arguing that an issuer whose main business is stablecoins has less incentive to favor any single DeFi venue.
Issuance is handled by Circle International Bermuda Limited, licensed as a Class F Digital Asset Business by the Bermuda Monetary Authority. Distribution runs through Circle Internet Financial LLC in the United States. The whitepaper describes future integrations that extend the model across chains without changing the central promise: every cirBTC remains backed 1:1, with reserve data verifiable on-chain.
A competitive field with a trust problem
The wrapped bitcoin market has long been dominated by WBTC, a joint venture historically involving BitGo, and by alternatives such as tBTC and LBTC from Lombard. Each has faced the same question from allocators: who holds the bitcoin, and can the backing be verified independently? WBTC moved its custody structure in 2024 after a change in ownership ties raised concerns among the DAOs that govern its contracts, and several large DeFi protocols temporarily blocked new WBTC mints. The episode showed how sensitive the market is to custody arrangements, and it opened space for issuers with cleaner regulatory profiles.
Circle’s answer is to make the reserve data continuously observable rather than attested at intervals. The company also points to its record with USDC, which publishes reserve composition and has survived bank runs and depeg episodes that tested its transparency claims. Skeptics note that Chainlink feeds depend on the oracle network’s own node set, so the design replaces one trust assumption with another rather than eliminating trust entirely. Circle’s response is that the disclosed reserve addresses let anyone bypass the oracle and count the bitcoin directly.
| Feature | cirBTC | Typical wrapped BTC |
|---|---|---|
| Backing | 1:1 native BTC | 1:1 native BTC |
| Custody | Circle National Trust, segregated | Varies by issuer |
| Reserve verification | Chainlink Proof of Reserve, on-chain | Periodic attestations |
| Regulator | Bermuda Monetary Authority, OCC-supervised trust | Varies |
| Planned chains | Ethereum now, Arc next | Often single-chain |
Ties into the Arc buildout
The launch follows closely on Circle’s Arc mainnet, the layer-1 blockchain the company opened last week with USDC as native gas and a validator set that includes BlackRock, DTCC, Visa and Mastercard. Circle says cirBTC will expand to Arc once approvals allow, making it one of the first wrapped assets natively available on the new chain. That sequencing is deliberate: a dollar stablecoin and a bitcoin collateral token are the two building blocks most on-chain markets need, and Circle now offers both under its own brand.
The commercial bet is that institutions prefer a single counterparty for stablecoin liquidity and bitcoin collateral, with verifiable reserves on both. Whether DeFi protocols adopt cirBTC at scale depends on liquidity incentives and on whether the Chainlink feed becomes a standard other issuers copy. Early supply figures are small, with the reserve dashboard showing a few dozen bitcoin against a few million dollars in tokens, so the launch is a statement of architecture more than a liquidity event. But the design sets a higher default for what transparency in wrapped assets looks like, and competitors will face questions about why their reserves are not observable the same way.