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name: bitcoin-l2-solv description: | Solv Protocol: SolvBTC / xSolvBTC tokenized Bitcoin distributed across many chains, custody behind Safe multisigs with a Vault Guardian and FROST signing partners. Migrated bridging from LayerZero to Chainlink CCIP on 7 May 2026. BRO Vault incident, 5 March 2026: 38.0474 SolvBTC (~$2.7M), fully compensated. USE WHEN: integrating SolvBTC, threat-modelling multi-chain wrapped BTC, reviewing BTCFi custody incidents. allowed-tools: Read, Grep, Glob

Solv Protocol (SolvBTC)

SolvBTC is a tokenized, yield-bearing Bitcoin asset deployed across many chains. Solv is the same team that authored the ERC-3525 semi-fungible token reference implementation, and its repo set shows SolvBTC contracts well outside EVM — SolvBTC-Solana-Contract, SolvBTC-Stellar-Contract, SolvBTC-SUI-Interface.

xSolvBTC is the yield-bearing variant; plain SolvBTC is the transferable base asset.

Figures from Solv's own 7 May 2026 announcement: $700M+ in tokenized Bitcoin across SolvBTC and xSolvBTC, $2.8B total managed assets. DefiLlama put Solv Protocol TVL at ~$577.3M on 15 September 2026. Those are different metrics measured on different dates; do not blend them. Re-check: https://defillama.com/protocol/solv-protocol

Custody and signing

• Solv Vault Guardian — a Safe (Gnosis) Guard contract. It "exclusively permits Safe Wallet with multiple signatures to execute operations within a defined range", i.e. the multisig is constrained to a whitelisted action set even when a quorum signs.
• FROST multi-sig partners — Solv announced institutional FROST signing partners on 30 March 2026. FROST gives threshold Schnorr signing that looks like a single key on-chain; see cryptography/frost for the protocol itself.
• Antalpha partnership for SolvBTC security (per the SolvBTC repo README).

Cross-chain

On 7 May 2026 Solv migrated SolvBTC and xSolvBTC bridging from LayerZero to Chainlink CCIP across all supported chains, deprecating the LayerZero bridges on Corn, Berachain, Rootstock and TAC. Stated rationale: cross-chain bridges "remain one of the most sensitive and high-risk areas in DeFi".

Practical consequence: SolvBTC balances on two different chains are not the same object, and a bridge compromise on the minority chain is a mint vector. Always check which bridge a given deployment is behind before treating SolvBTC as fungible across chains.

BRO Vault incident, March 2026

Solv's own post-incident review (published 30 March 2026) states:

• Identified and contained 5 March 2026.
• Loss: 38.0474 SolvBTC, approximately $2.7M at the time.
• Affected two participants in a single BRO Vault deployment — a standalone, non-public vault created for the Solv Token listing, not part of the standard product suite. No other products or user funds were affected.
• Stated cause is process, not mechanism: "the BRO Vault had not been subject to the same level of operational process and security rigor". The report does not disclose the technical vulnerability. Third-party write-ups calling it a "double-minting" bug are going beyond the primary source — do not repeat that label as fact.
• 100% of losses compensated as of 9 March 2026.
• Remediation: external audit review required for all contract deployments, plus formal risk assessment and change-management approval.

Source: https://solvfinanceblog-bwpvl.wpcomstaging.com/post-incident-review-bro-vault-incident-and-strengthened-security-commitments/

The transferable lesson matches the rest of this group: the Bitcoin side of a wrapped-BTC product is rarely what breaks. Peripheral deployments that inherit the brand but not the review process are.

Use cases

• BTC exposure inside DeFi on chains with no native BTC bridge.
• Yield aggregation — xSolvBTC routes to whatever strategy Solv is running, so diligence is on the strategy, not the token.
• Institutional rails via the Safe + Guardian + FROST stack.

Limitations

• Custodial in substance. A Safe multisig with a Guard is a policy-constrained federation. Bitcoin enforces nothing here.
• Strategy opacity — "yield-bearing" hides what is actually generating the yield; that is where the risk lives.
• Per-chain divergence — many deployments, many bridges, varying maturity.
• Incident precedent — the March 2026 loss was small and fully compensated, but it happened in a deployment outside the audited process. Ask which process a given vault went through.

See also

• lombard/SKILL.md
• babylon/SKILL.md
• threshold-tbtc/SKILL.md
• rootstock-rsk/SKILL.md