Wrapped Bitcoin (WBTC) is an ERC-20 token on Ethereum, backed 1:1 by real Bitcoin held in reserve. It solves a fundamental interoperability problem: native Bitcoin cannot interact with Ethereum smart contracts, leaving the largest crypto value pool unable to participate in lending, borrowing, trading, or yield farming. WBTC locks real BTC and issues an equivalent token, allowing holders to use their Bitcoin's value inside the DeFi ecosystem without selling their position.
Why Bitcoin needs wrapping
Bitcoin intentionally limits its scripting language for security, so it cannot execute smart contracts. Ethereum, by contrast, was built for smart contracts, and most DeFi protocols run on it. That creates a gap: Bitcoin is the largest store of value in crypto, yet it cannot natively plug into these applications. Wrapping bridges the gap by turning Bitcoin into an ERC-20 token, making it compatible with Ethereum's entire application layer. The ERC-20 standard defines rules for interchangeability, so a wrapped token can be lent, borrowed, swapped, and used as collateral just like any other Ethereum token.
Mint-and-burn mechanism: three actors
The 1:1 peg is maintained through a mint-and-burn process involving three parties: custodians (currently BitGo) hold the actual Bitcoin; merchants (e.g., exchanges) conduct KYC/AML checks and distribute WBTC; users initiate conversions.
To mint WBTC, a user requests from a merchant, who verifies identity and sends BTC to the custodian. The custodian locks the BTC and mints an equivalent amount of WBTC on Ethereum. To burn, the user submits a redemption request; the WBTC is destroyed, and the custodian releases the corresponding Bitcoin. Both minting and burning are recorded publicly on Bitcoin and Ethereum chains, with periodic proof-of-reserve audits for transparency.
Governance structure and the 2024 trust test
WBTC is governed by the WBTC DAO, a decentralized autonomous organization with a multi-signature wallet. Members can vote to add or remove custodians/merchants and modify smart contracts. In 2024, custodian BitGo announced a partnership with a firm linked to a controversial figure, sparking concern across DeFi. The incident highlighted a core risk: users trust custodians to safeguard the backing BTC, and changes in control or reputation can shake confidence. It also accelerated the rise of alternatives with different custody models.
Practical example: putting Bitcoin to work
Consider Ezra, who holds $2,000 worth of Bitcoin and wants to earn yield without selling. Native BTC cannot be deposited into Ethereum lending protocols. By converting his BTC to WBTC (via an exchange or directly through a merchant), Ezra obtains an Ethereum-compatible token that tracks BTC price 1:1. He can then lend it on Aave to earn interest, use it as collateral to borrow other assets, or supply it to liquidity pools for trading fees. WBTC transactions settle on Ethereum's faster block times, improving transfer speed.
Risks and trust assumptions
Holding WBTC is not the same as holding native Bitcoin. Key risks include: custodial risk (bankruptcy or hack of the custodian can break the peg); smart contract risk (vulnerabilities in WBTC contracts); bridge risk (failure in cross-chain mechanisms). Users must evaluate their trust in third parties before using WBTC.
Alternatives: cbBTC and tBTC
Several alternatives offer different custody approaches: Coinbase's cbBTC is centralized and regulated, prioritizing compliance and liquidity; Threshold's tBTC is more decentralized, managed by a group of independent signers without a single custodian. Choosing among them depends on one's preference for decentralization versus convenience.