CoinCorner, a British bitcoin exchange based in the Isle of Man, has launched a multisig custody service called Vault. The service splits control of customer keys between CoinCorner and its US partner AnchorWatch, and holdings are insured by Lloyd's of London. It's aimed at owners who want cold-storage security without managing hardware themselves, and it arrives weeks after a firmware bug in Coldcard wallets drained roughly $115 million from single-signature users.
How the Vault works
Customers can open a Vault and deposit any amount, but bitcoin doesn't move into the insured wallet immediately. Transfers typically happen on the first working day of the following month. Top-ups are allowed at any time, and holdings are verifiable on-chain via a wallet address provided by CoinCorner. Customers also define their own identity verification rules before funds can move.
Why the Coldcard hack matters
The launch follows the Coldcard wallet hack, where single-signature wallet users lost funds due to a firmware bug that caused weak seed generation. Approximately $115 million was lost. That incident highlighted the risks of single-sig setups, where one compromised key can drain an entire wallet. Multisig, by contrast, requires multiple keys to authorize a transaction, making it harder for an attacker to walk away with funds.
Key distribution handled for you
Traditional multisig setups are technically demanding. Users have to generate, store, and back up multiple keys correctly, and a single mistake can lock funds out forever. CoinCorner says it simplifies this by handling key distribution on the customer's behalf, reducing the complexity that has kept many people away from multisig. The service charges an annual fee of 1.5%.
First of its kind?
CoinCorner claims it is the first service of its kind globally. That's a bold statement, but the combination of multisig, insurance, and a managed key split is unusual. Whether it holds up will depend on how the service performs in practice.
Customers can open a Vault and deposit any amount now. The first batch of deposits will move into the insured wallet on the first working day of October, which is when the on-chain addresses will start showing activity.
