Wrapped Bitcoin (WBTC)

What Is Wrapped Bitcoin?

Wrapped Bitcoin (WBTC) is an ERC-20 token on Ethereum that represents Bitcoin at a 1:1 ratio. Each WBTC token is backed by one real BTC held in reserve by designated custodians. The token launched on January 31, 2019, as a joint project between BitGo, Kyber Network, and Ren Protocol, with the goal of bringing Bitcoin's liquidity into Ethereum's DeFi ecosystem.

The core problem WBTC solves: Bitcoin and Ethereum are separate blockchains with incompatible transaction formats. BTC cannot natively interact with Ethereum smart contracts. By locking BTC with a custodian and issuing an equivalent ERC-20 token, WBTC creates a wrapped asset that moves freely across Ethereum's DeFi protocols while maintaining a peg to Bitcoin's value.

As of mid-2026, approximately 116,000 to 120,000 WBTC are in circulation, representing roughly $7 to $8 billion in value. This makes WBTC one of the largest TVL contributors in DeFi and a top-20 cryptocurrency by market capitalization.

How It Works

WBTC operates through a three-party system: custodians, merchants, and a DAO. This structure separates the roles of holding reserves, processing user requests, and governing the protocol.

The Mint and Burn Process

Creating and redeeming WBTC follows a mint and burn mechanism:

1. A user sends BTC to an authorized merchant and requests WBTC
2. The merchant performs KYC/AML verification, then forwards the BTC to the custodian (BitGo or BiT Global)
3. The custodian verifies receipt of BTC and mints an equivalent amount of WBTC on Ethereum
4. The newly minted WBTC is sent to the merchant, who delivers it to the user

Redemption reverses this process: the merchant sends WBTC to the custodian for burning, and the custodian releases the corresponding BTC. Only authorized merchants can mint or redeem directly. Retail users typically acquire WBTC by swapping on decentralized exchanges or through centralized platforms.

Custody Structure

Bitcoin reserves backing WBTC are secured using a 2-of-3 multisig wallet. Following a restructuring in August 2024, the three key holders are:

• BitGo Inc. (United States)
• BitGo Singapore
• BiT Global (Hong Kong)

BitGo controls two of the three keys, meaning BiT Global cannot unilaterally move funds. Any transaction requires at least two signers from different jurisdictions, creating what BitGo describes as "multi-jurisdictional and multi-institutional custody."

WBTC DAO Governance

The WBTC DAO oversees the protocol through a multi-signature governance wallet. DAO members include custodians, merchants, and other DeFi institutions such as Kyber Network and Compound. The DAO controls the ability to add or remove merchants and custodians and to approve protocol upgrades.

Smart Contract Details

The WBTC contract is deployed on Ethereum at address 0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599. It implements the standard ERC-20 interface with additional minting and burning functions restricted to authorized addresses:

// Simplified WBTC minting flow (Solidity)
interface IWBTC {
    function mint(address to, uint256 amount) external returns (bool);
    function burn(uint256 amount) external returns (bool);
    function balanceOf(address account) external view returns (uint256);
    // Only callable by authorized merchants/custodian
    // 1 WBTC = 1e8 (8 decimal places, matching BTC)
}

Proof of Reserves

WBTC uses multiple mechanisms to prove that every circulating token is backed by real Bitcoin:

• On-chain transparency: the Bitcoin reserve addresses are publicly viewable, allowing anyone to verify the BTC balance on the Bitcoin blockchain
• Chainlink Proof of Reserve: an automated oracle feed that provides real-time on-chain verification of WBTC collateralization, queryable by smart contracts
• The wbtc.network dashboard publishes live reserve data showing BTC held against circulating WBTC supply
• All minting and burning transactions are visible on both the Ethereum and Bitcoin blockchains, creating a full audit trail

The 2024 Custody Controversy

In August 2024, BitGo announced a plan to transfer WBTC custody to a joint venture with BiT Global, a Hong Kong-based company linked to Justin Sun (founder of the TRON blockchain). The original proposal would have given BiT Global control of two of three multisig keys, effectively granting a Sun-associated entity majority control over billions of dollars in Bitcoin reserves.

The DeFi community responded with alarm. Within days, MakerDAO's (now Sky) risk team proposed reducing WBTC exposure, citing concerns about the custody change. BitGo quickly revised the key structure on August 14, 2024, keeping two of three keys under BitGo entities and giving BiT Global only one.

Despite the revision, the damage to confidence was significant:

• Sky (formerly MakerDAO) voted 88% in favor of offboarding WBTC as collateral, though the plan was later paused after discussions with BitGo's CEO
• Aave risk analysts recommended reducing WBTC loan-to-value ratios and lowering supply caps
• Coinbase delisted WBTC entirely, citing "unacceptable risk," and launched its own wrapped Bitcoin token (cbBTC) in September 2024
• BiT Global filed a lawsuit against Coinbase seeking over $1 billion in damages, alleging the delisting was anticompetitive: the case was dismissed with prejudice in June 2025

This controversy underscored a fundamental tension in wrapped assets: custodial tokens require trust in the custodian, and changes to custody arrangements can destabilize an entire DeFi ecosystem built on that trust.

Use Cases

WBTC enables Bitcoin holders to participate in Ethereum's DeFi ecosystem without selling their BTC exposure:

• Lending and borrowing: deposit WBTC as collateral on protocols like Aave or Compound to borrow stablecoins or other assets, enabling leveraged positions without liquidating Bitcoin holdings
• Liquidity provision: supply WBTC to AMM pools on Uniswap, Curve, or Balancer to earn trading fees from BTC-paired swaps
• Yield generation: stake WBTC in yield aggregators or lending protocols to earn interest on otherwise idle Bitcoin
• Cross-chain trading: trade BTC-denominated value on Ethereum DEXs without using centralized exchanges, taking advantage of Ethereum's deeper DeFi liquidity

Alternatives to WBTC

The WBTC custody controversy accelerated development of alternative wrapped Bitcoin tokens, each with different trust assumptions:

Decentralized alternatives like tBTC eliminate the single-custodian risk but introduce complexity: threshold signing requires coordination among multiple independent operators, and the minting process is slower. Centralized alternatives like cbBTC trade one custodian for another, shifting trust rather than removing it.

Why Native Bitcoin Solutions Matter

All wrapped Bitcoin tokens share a fundamental limitation: they require bridging BTC from the Bitcoin blockchain to another chain. This introduces custodial risk (centralized bridges) or smart contract risk (decentralized bridges), and bridges have historically been among the most exploited components in crypto.

Native Bitcoin Layer 2 solutions take a different approach entirely. Instead of wrapping BTC into a token on another chain, they extend Bitcoin's capabilities directly. Spark, for example, enables self-custodial Bitcoin transactions with smart contract functionality without requiring users to trust a custodian or bridge their BTC to a separate blockchain. Users retain control of real Bitcoin rather than holding a synthetic representation of it.

This distinction matters for risk management: with WBTC, a custodian hack or regulatory seizure can break the peg and strand holders with a valueless token. With native Layer 2 solutions, the underlying Bitcoin never leaves the Bitcoin security model.

Risks and Considerations

Custodial Risk

WBTC requires trusting centralized custodians to hold Bitcoin reserves honestly and securely. If a custodian is compromised, becomes insolvent, or acts maliciously, WBTC holders could lose their backing. The 2024 custody controversy demonstrated how quickly confidence can erode when custody arrangements change.

Depeg Risk

WBTC briefly traded at a discount to BTC in November 2022, dropping to approximately 0.9852 BTC during the FTX collapse. Alameda Research had been the largest WBTC merchant by minting volume (over 100,000 WBTC minted), and their bankruptcy raised fears about reserve integrity. Although BitGo confirmed 1:1 backing and the peg recovered, the episode showed that market confidence in the redemption mechanism is as important as the reserves themselves.

Smart Contract Risk

Bugs or exploits in the ERC-20 contract or minting logic could allow attackers to mint unbacked WBTC or prevent redemptions. While the contracts have been audited, no smart contract is immune to zero-day vulnerabilities.

Regulatory Risk

BitGo is a regulated US entity with the ability to freeze assets. The WBTC contract includes administrative functions that could restrict transfers. Regulatory pressure in any of the three custody jurisdictions (US, Singapore, Hong Kong) could force policy changes or operational restrictions. For users who value Bitcoin's censorship resistance, a blacklist-capable wrapper introduces a trust assumption that native BTC does not carry.

Redemption Bottleneck

Only authorized merchants can mint and redeem WBTC directly. Retail users depend on secondary market liquidity. If merchants are removed, go offline, or face regulatory restrictions, the path between WBTC and actual BTC narrows, potentially causing the token to trade at a discount.

This glossary entry is for informational purposes only and does not constitute financial or investment advice. Always do your own research before using any protocol or technology.