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Documentation Index

Fetch the complete documentation index at: https://developers.circle.com/llms.txt

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cirBTC is Circle Wrapped Bitcoin—a tokenized representation of Bitcoin (BTC) issued by Circle on Ethereum and Arc. Every cirBTC is backed 1:1 by native BTC held at a regulated entity in the Circle group of companies. The BTC is held for the exclusive benefit of cirBTC holders and segregated from Circle’s corporate assets.

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Why wrap Bitcoin?

Bitcoin is the most widely held digital asset, yet it cannot natively interact with smart contracts, meaning it cannot be used for lending, borrowing, or complex trading without being wrapped. cirBTC solves this by creating a tokenized version of BTC that operates on smart contract blockchains, transforming idle Bitcoin into productive capital.
  • 1:1 backed by native BTC—every cirBTC is redeemable for the underlying Bitcoin
  • Neutral issuer—Circle doesn’t operate a competing exchange or lending protocol
Paired with USDC, cirBTC enables institutional workflows such as posting cirBTC as collateral to borrow USDC and access capital without selling the underlying Bitcoin position.