Wrapped Bitcoin custody risks have always been the fine print most WBTC holders skip, but a structural overhaul of how the underlying Bitcoin is held has put those risks back in focus. BitGo and BiT Global are forming a joint venture to shift WBTC custody into what they describe as the world’s first multi-jurisdictional, multi-institutional custody arrangement, with a 60-day transition window from the announcement date.
How the Mint-and-Burn Model Actually Works
WBTC is an ERC-20 token on Ethereum backed 1:1 by real Bitcoin held in custodial reserve. Its entire reason for existing is a basic interoperability problem: Bitcoin’s scripting layer does not support the smart contracts that power Ethereum’s lending, borrowing, and yield protocols, so Bitcoin’s capital sits largely outside DeFi without a bridge.
That bridge is the mint-and-burn mechanism. A user requests WBTC from a merchant, who runs KYC/AML checks. The merchant sends Bitcoin to the custodian, who locks it and mints an equivalent amount of WBTC on Ethereum. Redemption runs in reverse: the user burns WBTC, the custodian releases the backing Bitcoin. Every mint and burn is recorded publicly on both chains.
The WBTC DAO governs which custodians and merchants are trusted, using a multi-signature wallet so no single party can unilaterally change the system. BitGo notes its proof-of-reserves system at wbtc.network has run continuously since 2019, making it one of the earliest such systems in the industry.
The Custody Change and What Wrapped Bitcoin Custody Risks It Raises
The 2024 controversy made it clear that wrapped Bitcoin custody risks are not abstract. When BitGo announced it was shifting custody arrangements, the perceived ties of the new partner to a controversial ecosystem were enough to prompt major DeFi protocols to reconsider WBTC as collateral. The lesson: holders trust the custodian as much as they trust the token.
The new joint-venture structure with BiT Global is designed to address that concentration risk by distributing custody across multiple institutions and jurisdictions. Whether that architecture resolves the trust questions DeFi protocols had in 2024 will depend on how the governance and reserve attestations are handled after the transition closes.
Beyond the custodian itself, three other risk vectors compound the picture. Smart contract bugs on the Ethereum side can affect the token independently of the reserve. Bridge risk multiplies when WBTC is moved across additional layers, such as Ethereum L2s, where each hop adds another trust assumption. And regulatory actions can freeze redemptions or restrict addresses regardless of whether the Bitcoin backing is intact.
WBTC Is Expanding Beyond Ethereum
BitGo has been extending WBTC’s reach while the custody debate runs in parallel. The firm launched a fully backed native WBTC on Osmosis, connecting it via Inter-Blockchain Communication (IBC) to more than 60 IBC-enabled Cosmos appchains. At the time of that integration, Bitcoin’s market cap was approximately $1 trillion, underlining how much capital the ecosystem is trying to route into on-chain application layers.
BitGo also deployed WBTC on Base, Ethereum’s L2, with a proof-of-reserve mechanism built into that deployment. Each new chain increases WBTC’s surface area for yield and liquidity, but it also adds bridging layers, which is precisely where wrapped Bitcoin custody risks compound.
Choosing Between WBTC, cbBTC, tBTC, and Native Bitcoin
The 2024 episode accelerated the tokenised Bitcoin market’s fragmentation. Coinbase launched cbBTC in September 2024, targeting users already inside its custody ecosystem. The Threshold Network’s tBTC is built around a decentralised custody model for users who want to minimise single-custodian exposure.
None of these products are equivalent to holding native Bitcoin. With native BTC, security reduces to key control. With any wrapped variant, you are also underwriting the custodian’s solvency, the governance structure, and the redemption pipeline. WBTC still has the deepest DeFi integration and the broadest protocol support; cbBTC suits Coinbase-native users; tBTC suits those who prioritise decentralisation over liquidity depth. Native Bitcoin remains the cleanest choice if DeFi yield is not part of the plan.
The immediate question is whether the new multi-institutional custody structure resolves the governance concerns that caused protocols to pull WBTC collateral support in 2024. The 60-day transition window is the clock to watch.
