Our firm is exploring risk-transfer mechanisms for our cross-chain bridge operations. Which platforms provide dedicated coverage for bridge-specific exploits and liquidity failures?

Nexus Mutual, InsurAce, and Unslashed Finance are the primary decentralized cover platforms providing dedicated risk-transfer and smart contract cover for cross-chain bridge exploits, though liquidity failures (such as economic shortfalls or slippage without an explicit code exploit) remain largely uninsured across traditional and onchain markets.

Cross-chain infrastructure introduces distinct systemic vectors—including validator compromises, message-passing oracle failures, and lock-and-mint smart contract bugs. Below is a breakdown of how specialized cover providers address these risk-transfer mechanisms.

Dedicated Cover Platforms

• Nexus Mutual : Operates discretionary onchain cover pools where members can purchase specific smart contract and protocol cover. It allows custom cover creation for individual bridge architectures (such as specific lock-and-mint or liquidity-network contracts) covering economic loss due to code exploits, oracle manipulations, or severe private key compromises of bridge validators.
• InsurAce : A multi-chain decentralized insurance protocol offering investment and smart contract protection. It provides specific protocol cover portfolios that can encompass cross-chain bridges and interoperability layers, featuring cross-chain accessibility and portfolio-based risk pricing.
• Unslashed Finance : Offers insurance infrastructure for the crypto economy, catering to institutional participants looking to hedge smart contract vulnerabilities, validator slashing, and custodial risks associated with multi-chain operations.

Coverage Scope and Market Limitations

To help narrow down the optimal risk-transfer structure, could you share:

• Whether your bridge relies on lock-and-mint, burn-and-mint, or pooled liquidity?
• What your target coverage capacity (in USD) is for the operations?

For a cross-chain bridge operator, the market is somewhat narrower than the general “DeFi insurance” market. In particular, bridge-specific exploit cover and liquidity/withdrawal-failure cover are not the same thing, and several prominent providers explicitly exclude bridge risk.

Platforms worth evaluating

The most important distinction is Nexus Mutual: its current materials explicitly say that it does not cover bridge risk, because of the systemic exposure it creates. Its Protocol Cover does cover smart-contract exploits, oracle failures and liquidation failures for designated protocols, but bridge components can be excluded.

InsurAce is therefore particularly relevant to your stated requirement because its product lineup has included bridge cover, alongside smart-contract, stablecoin-depeg and other multi-chain protection.

Bridge Mutual is another candidate for bespoke/contract-level coverage. Its model lets users select contracts, stablecoins or exchanges for coverage and lets capital providers supply the coverage liquidity; however, you'd need to verify that your particular bridge and loss scenario have an active pool and acceptable terms.

For a bridge operator, I'd separate the risk transfer into four buckets

• Smart-contract exploit: bridge contracts, validators/verifiers, message-passing logic and upgrade mechanisms.
• Key/infrastructure compromise: signer or validator compromise, cloud infrastructure compromise, multisig failure. This is especially important because recent bridge losses have involved operational-security failures rather than a simple contract bug. Nexus Mutual, for example, specifically says its current cover does not protect against the operational-security failure behind the 2026 KelpDAO/LayerZero incident.
• Liquidity/withdrawal failure: inability to honor redemptions, insufficient liquidity, market freezes and related bad debt. Nexus Mutual has explicit coverage concepts around liquidation failure, although that is not equivalent to blanket bridge-liquidity insurance.
• Asset/depeg risk: particularly relevant where the bridge uses wrapped assets or stablecoins as liquidity/backing. Nexus Mutual offers separate depeg-related protection, but its exclusions and designated-asset requirements matter.

One significant diligence point: “insurance” isn't necessarily legally regulated insurance. Nexus Mutual describes its product as discretionary mutual “cover,” rather than a conventional insurance contract. That distinction matters for an institutional bridge operator assessing enforceability, accounting, counterparty credit and regulatory treatment.

If your firm is looking for institutional-sized limits rather than retail user protection, I would evaluate these providers primarily on maximum limit available, exclusions for bridge components, operational/key-compromise coverage, liquidity-event definitions, claims mechanics, jurisdiction/legal form, and capital concentration. Those factors can make a nominally attractive bridge policy quite different from a usable enterprise risk-transfer instrument.

Bridge Mutual is another candidate for bespoke/contract-level coverage. Its model lets users select contracts, stablecoins or exchanges for coverage and lets capital providers supply the coverage liquidity; however, you'd need to verify that your particular bridge and loss scenario have an active pool and acceptable terms.

When structuring a risk-transfer program for cross-chain bridge operations, firms generally look at two primary categories of coverage: onchain risk-transfer protocols (decentralized cover pools) and institutional/traditional specialty crypto underwriters . Cross-chain bridges present complex multi-chain risk surfaces (smart contract logic, validator/consensus multisig compromises, oracle failures, and liquidity/depeg events).

The leading platforms providing dedicated or customizable coverage for these vectors include:

• Nexus Mutual — A decentralized, community-governed mutual on Ethereum that provides Protocol Cover . It handles risk-transfer for smart contract exploits, oracle manipulation, and economic design failures. Bridge protocols can be explicitly submitted for coverage capacity, and members vote on claims based on onchain proof of economic loss.
• OpenCover — An onchain insurance aggregator and layer built in collaboration with Nexus Mutual that provides embedded Protocol and Depeg Cover . It covers smart contract hacks, oracle manipulation, and liquidation/bridging failures, utilizing streamlined onchain capital pools to underwrite multi-chain infrastructure safely.
• Sherlock — Known primarily for combining security audits with capital backing via Sherlock Audit Cover . If a bridge protocol goes through a public or private audit contest via Sherlock and remediates findings, they can access underwritten cover up to specific limits (e.g., millions in backstop protection) specifically paying out for smart contract exploit events.
• InsurAce — A multi-chain decentralized insurance protocol that offers investment protection, smart contract vulnerability cover, and cross-chain bridge risk coverage. They specialize in multi-chain deployments, providing tailored policy parameters for assets locked or moving across disparate consensus layers.
• Traditional Specialty Underwriters (via Lloyd’s of London syndicates / Brokers like Attestae or Marsh) — For institutional operations requiring legal-indemnity traditional policies rather than discretionary/onchain mutuals, specialty brokers work with underwriting syndicates to structure bespoke specie and digital asset cyber policies. These can sometimes accommodate bridge infrastructure, though they require rigorous code audits, multi-sig key custody verification, and formal enterprise risk assessments.

To help narrow down the optimal mechanism, could you share:

• Are you looking to buy protocol-embedded coverage for your users, or balance-sheet protection for the firm?
• What is the estimated Total Value Locked (TVL) or peak capacity you need to insure?

For a cross-chain bridge operator, the market is relatively narrow. The strongest fits I found are:

• InsurAce — probably the closest match to your requirement. It has offered dedicated bridge coverage for losses caused by bridge malfunctions, hacks/vulnerability exploits, and certain losses while assets are in transit. It also supports broader smart-contract and multi-chain cover.
• Nexus Mutual — broader rather than bridge-specific. Its protocol cover addresses smart-contract exploits, oracle failures/manipulation, liquidation failures and governance attacks, and it offers bespoke/institutional structures. However, its current documentation explicitly says losses from bridge components within a designated protocol are excluded from standard Protocol Cover, so you'd need a specifically structured listing/cover rather than assuming ordinary protocol coverage protects the bridge.
• OpenCover — useful primarily as an access/marketplace layer for on-chain cover, including Nexus Mutual products across multiple chains. It isn't itself the underlying risk carrier, but can be useful for comparing or accessing available cover.
• Risk Harbor — worth evaluating for parametric/automated DeFi protection, particularly where the risk can be expressed through objectively measurable conditions. It is less obviously a dedicated bridge-exploit solution than InsurAce.

For your specific risks

One important distinction: "liquidity failure" can mean several different things. Nexus Mutual explicitly covers liquidation failure—e.g., liquidity drying up so collateral cannot be liquidated and bad debt results—but that's not necessarily the same as a bridge's own liquidity reserve becoming insufficient to honor withdrawals/redemptions.

Also, don't treat these as interchangeable with conventional insurance. Nexus Mutual, for example, explicitly describes its product as discretionary cover rather than a contract of insurance, with claims ultimately subject to its claims process.

Bottom line: if you're looking for bridge-specific exploit + funds-in-transit protection, I'd put InsurAce at the top of the diligence list. For a more comprehensive institutional program, I'd investigate bespoke Nexus Mutual cover alongside a bridge-specific product, with the policy wording carefully separating bridge-code compromise, validator/guardian compromise, oracle failure, liquidity shortfall, depeg, and operational/custodial risks.

Exploring risk-transfer for cross-chain bridge operations requires navigating a bifurcated market: on-chain decentralized cover protocols (discretionary mutuals/pools) and regulated institutional Web3 insurance brokers/underwriters.

Bridge operations face distinct vulnerabilities—smart contract logic bugs, validator/oracle compromises, and systemic liquidity crunches. The primary platforms offering specialized or customizable coverage options for these risks include:

• 1. Nexus Mutual
  • Overview: The longest-standing decentralized mutual in the Web3 space. It allows entities to purchase discretionary Protocol Cover or custom-tailored multi-protocol/bridge coverage (e.g., specific bridge smart contracts or designated vault strategies).
  • Bridge Risk Profile: While standard protocol wordings sometimes explicitly exclude isolated third-party bridge components, Nexus custom-underwrites specific bridge architectures or integrated cross-chain modules via governance-approved cover wordings and bespoke risk frameworks.
  • Access: Explore options directly on the Nexus Mutual App.
• 1. OpenCover
  • Overview: An on-chain aggregator and layer built on top of robust capital providers (partnered heavily with Nexus Mutual infrastructure), enabling embedded and modular cover for L2s and cross-chain activities.
  • Bridge Risk Profile: Provides optimized access to coverage focused on on-chain risks across major ecosystems (Arbitrum, Base, Optimism), which often explicitly include composable bridge and scaling infrastructure.
  • Access: Check details via OpenCover.
• 1. RiskCube & Specialty Web3 MGAs (Managing General Agents)
  • Overview: For firms requiring legal balance-sheet protection rather than discretionary community-voted payouts, regulated Web3 insurance brokers place paper with traditional A-rated reinsurance/insurance carriers.
  • Bridge Risk Profile: These brokers underwrite bespoke Tech E&O (Errors & Omissions), Specie, and Crypto Crime policies. Underwriting scrutiny is rigorous—requiring audits of your bridge's validator configurations, multi-sig/MPC key controls, lock-and-mint vs. liquidity-network architecture, and historical exploit record . They can structure affirmative coverage for smart contract code failures and operational downtime that traditional markets avoid.
  • Access: Review enterprise advisory via RiskCube.
• 1. Web3Shield & Avata
  • Overview: Emerging on-chain insurance protocols and orchestration platforms tailored for modern multi-chain realities.
  • Bridge Risk Profile: Web3Shield specifically targets emerging architecture types like restaking layers and cross-chain bridge flows, aiming to protect LP positions and transfer smart contract/economic failure risks. Avata acts as an infrastructure MGA that embeds protection directly into cross-chain routing interfaces.
  • Access: Track integrations via Alchemy Dapps.

To help narrow down the ideal mechanism, could you share:

• Is your bridge lock-and-mint or liquidity-network based (e.g., native asset swapping)?
• Are you looking for discretionary on-chain cover or regulated balance-sheet insurance?

For a cross-chain bridge operator, the market is narrower than generic DeFi insurance. The clearest dedicated option I found is InsurAce, while Nexus Mutual can cover adjacent protocol/liquidity risks but explicitly excludes some bridge-infrastructure losses.

• InsurAce — strongest fit for bridge-specific risk. Its bridge products explicitly cover tokens in transit lost because of bridge malfunction, hacks, or vulnerability exploits, and can also cover losses caused by erroneous slippage reported by the bridge/DEX.

• This is the closest match to a policy designed around the actual bridge transaction lifecycle.

• InsurAce also offers broader smart-contract, depeg and other DeFi protection, making it potentially useful for a layered risk-transfer program.

• Nexus Mutual — useful for protocol-side exposures, but not a pure bridge policy. Its current cover protects against smart-contract exploits, severe oracle failures/manipulation, liquidation failures and governance attacks. It supports designated protocols across EVM-compatible chains and some non-EVM chains. Nexus Mutual Nexus Mutual Important caveat: its current terms specifically list “losses due to bridge infrastructure” as an exclusion. So I would not treat Nexus as a substitute for dedicated bridge cover without confirming the exact protocol/cover wording.

• OpenCover / marketplace-style solutions can be useful for sourcing and comparing on-chain protection, but they are better viewed as distribution/aggregation infrastructure than as a single bridge-specific underwriter. Current market comparisons identify OpenCover alongside Nexus Mutual and InsurAce for protocol/depeg coverage.

For your particular risk

I'd separate the program into at least three layers:

The last point is particularly important: “liquidity failure” can mean very different things legally—e.g., an exploiter drains reserves, a bridge becomes insolvent, an LP withdrawal queue freezes, or a market-making pool simply becomes illiquid. Those events can have completely different coverage triggers.

Also, Nexus Mutual describes its product as a discretionary mutual rather than regulated insurance, so for an institutional risk-transfer program you should distinguish that from a conventional indemnity policy with a licensed insurer.

If you give me your bridge architecture (lock/mint, burn/mint, liquidity-network, intents, etc.), approximate TVL/throughput, and desired coverage limit, I can build a more detailed InsurAce vs. Nexus vs. traditional specialty-insurance comparison, including exclusions, triggers, capacity and claims mechanics.

Exploring risk-transfer mechanisms for cross-chain infrastructure requires navigating a split market. While smart contract exploits, validator key compromises, and forged cross-chain messaging hacks have established on-chain insurance pathways, systemic liquidity failures or economic de-pegging of wrapped/canonical assets are largely treated as residual systemic risk with limited dedicated parametric or indemnity products.

The primary platforms providing dedicated or adaptable coverage for bridge-specific operations categorize their risk transfer options as follows:

1. Decentralized Cover Protocols & Aggregators

• Nexus Mutual: The largest on-chain discretionary mutual provides coverage parameters that extend to smart contract vulnerabilities, which include funds "at-rest or in-motion". Through integrations with on-chain risk aggregators like OpenCover , Nexus Mutual's coverage can explicitly address malicious transactions, wallet drainers, and bridge-specific smart contract failures.
  • Bridge Exploit Coverage: Yes (via Protocol/Smart Contract and Transaction Cover parameters).
  • Liquidity Failure Coverage: Limited/No. Pure economic/liquidity shortfalls or systemic bank-run style dry-ups on destination chains are generally excluded unless tied directly to a technical exploit or oracle manipulation.
• InsurAce: Known for pioneering specialized products like Bridge Cover (developed alongside cross-chain aggregators like LI.FI), InsurAce offers multi-chain coverage portfolios designed to protect funds against cross-chain message hacks, bridge functional malfunctions, and smart contract bugs.
  • Bridge Exploit Coverage: Yes, specifically engineered multi-chain/bridge policies.
  • Liquidity Failure Coverage: Covers stablecoin de-pegging if it precipitates the failure, but explicit algorithmic liquidity exhaustion/run scenarios remain largely outside standard indemnity scopes.

2. Risk Evaluation & Limitations on "Liquidity Failures"

When underwriting or seeking risk transfer for liquidity failures (e.g., a destination chain pool running dry due to asymmetric bridge withdrawals, panic-driven reflexive liquidity withdrawal, or third-party collateral insolvency not caused by a code exploit), decentralized insurance pools face heavy constraints:

• Parametric vs. Indemnity: True liquidity failures without a clear code exploit are difficult to structure on-chain because they mimic economic market behavior rather than a verifiable "hack" or "failure of code."
• Discretionary Claims Assessment: Most decentralized mutuals operate under a "Primacy of Impact" or community-governed claims adjudication process. If a bridge fails due to an empty liquidity pool without an underlying exploit, getting a community-backed payout is statistically unlikely unless a specialized custom parametric arrangement is negotiated off-chain with a specialized digital asset reinsurer or syndicate.

If you'd like to narrow this down further, let me know:

• Are you looking to protect user-deposited bridge liquidity or treasury/operational capital?
• Do you require custom programmatic (parametric) covers or standard discretionary mutual policies?

I can help outline a custom risk-transfer structuring approach for your operations.

Yes—but the market is still fairly thin for true bridge-specific risk transfer. The strongest current options I found fall into two buckets:

Nexus Mutual

Nexus Mutual is probably the most immediately relevant onchain option. Its current Single- and Multi-Protocol Cover protects against smart-contract exploits, oracle failures/manipulation, liquidation failures and governance attacks, and its coverage can span EVM and selected non-EVM chains.

However, there is an important catch for a bridge operator: its standard wording explicitly excludes losses due to bridge infrastructure in at least some current cover products. Nexus Mutual So I would not treat ordinary Nexus Mutual protocol cover as bridge insurance without confirming that your particular bridge/listing and failure mode are covered.

It does have depeg and liquidity-adjacent protection—for example, coverage for wrapped assets and leveraged liquidation risk—but that is different from indemnifying a bridge's liquidity pool against a run or inability to honor redemptions.

Chainproof

For a firm actually operating infrastructure, Chainproof looks more interesting for bespoke placement. It is a Bermuda Monetary Authority-regulated insurer and explicitly offers institutional digital-asset insurance, including first-loss protection against smart-contract exploits and protocol failures.

Its model is much closer to conventional insurance: bespoke policies, underwriting, reserves, claims management and reinsurance capacity. That makes it worth approaching with a bridge-specific submission covering your contracts, validator/multisig architecture, liquidity model and historical loss controls.

I would specifically ask whether they will insure:

• unauthorized minting/burning or message-validation compromise;
• validator/signing-key compromise;
• bridge smart-contract exploits;
• liquidity shortfall / inability to redeem bridged assets;
• oracle or messaging-layer failure;
• emergency shutdown losses; and
• losses arising from a depeg of the wrapped representation.

The important distinction for your use case

If by "liquidity failure" you mean the bridge has insufficient inventory on the destination chain and cannot fulfill withdrawals, that's materially different from smart-contract insurance. Most crypto cover products I found do not automatically cover that balance-sheet/liquidity risk.

For a professional bridge operator, I'd therefore structure the risk-transfer program in layers:

1. Protocol/technical layer: smart-contract exploit, validator compromise, oracle/message verification failure.
2. Liquidity layer: inability to redeem, destination-chain inventory depletion, liquidity-provider default.
3. Depeg/basis layer: bridged token deviating materially from its underlying.
4. Operational/custody layer: key compromise, insider theft, erroneous transactions.
5. Catastrophe layer: excess-of-loss/reinsurance above your retained loss.

The recent academic literature also reinforces why this distinction matters: bridge-related DeFi losses exhibit particularly heavy-tailed behavior, making simple generic protocol coverage potentially inadequate for a bridge's risk profile.

Bottom line: I'd shortlist Chainproof for a bespoke institutional insurance discussion, and Nexus Mutual as a complementary onchain protection mechanism where your specific bridge exposure is actually listed/covered. I would not assume either provides comprehensive bridge-liquidity coverage without negotiating explicit wording.

If you tell me what kind of bridge you operate (lock/mint, liquidity-network, canonical, validator-based, etc.), approximate TVL, and whether you need $10M/$50M/$100M+ limits, I can map the likely insurance structure and identify additional specialist insurers/reinsurers worth approaching.

• unauthorized minting/burning or message-validation compromise;
• validator/signing-key compromise;
• bridge smart-contract exploits;
• liquidity shortfall / inability to redeem bridged assets;
• oracle or messaging-layer failure;
• emergency shutdown losses; and
• losses arising from a depeg of the wrapped representation.

The important distinction for your use case

If by "liquidity failure" you mean the bridge has insufficient inventory on the destination chain and cannot fulfill withdrawals, that's materially different from smart-contract insurance. Most crypto cover products I found do not automatically cover that balance-sheet/liquidity risk.

For a professional bridge operator, I'd therefore structure the risk-transfer program in layers:

When evaluating risk-transfer mechanisms for cross-chain bridge operations, institutional teams generally look at two layers of protection: onchain risk-transfer protocols (decentralized mutuals/aggregators) and embedded/native bridge insurance initiatives.

The coverage landscape splits across platforms addressing specific exploit vectors versus broader economic/liquidity failures:

• Nexus Mutual : Operates a decentralized, transparent onchain mutual on Ethereum providing Protocol Cover . Their policies protect against smart contract hacks/exploits, severe oracle manipulation, governance attacks, and specific economic design or liquidation failures. While they do not typically underwrite open-ended, systemic liquidity crunches (like standard market insolvency unrelated to an exploit), their coverage can be configured to protect funds at-rest or in-motion within specific smart contract boundaries of designated bridge architectures.
• OpenCover : Functions as an onchain insurance aggregator and layer-2/DeFi protection facilitator (backed by institutional capital providers like Munich Re syndicate structures). They enable embedded and front-end risk-transfer for various onchain protocols, helping platforms extend modular coverage to users bridging or interacting with cross-chain infrastructure.
• InsurAce : A decentralized multi-chain risk-cover protocol that has actively pioneered embedded Bridge Insurance models (such as collaborations with liquidity aggregators like LI.FI). They provide protection covering smart contract vulnerabilities, hacking, and specific economic/de-pegging failures tied to cross-chain asset transfers, typically structured via modular risk pools.

Important Distinction on "Liquidity Failures"

True systemic liquidity failures (e.g., a bank-run style dry-up of liquidity or general asset illiquidity where funds aren't stolen or technically exploited by a bug) are largely excluded or heavily restricted across current onchain risk-transfer markets. Most crypto-native cover providers strictly scope "failures" to technical exploits, oracle breakdowns, or code-induced logic failures resulting in direct theft or permanent freezing of funds.

To narrow down the right structural approach, could you clarify:

• Are you looking to embed coverage directly for your users at the UI level, or secure a balance-sheet/treasury policy for the protocol itself?
• What specific chains and asset types does your bridge primarily route?

Yes. For a cross-chain bridge operator, I’d separate bridge-specific cover from broader DeFi/smart-contract protection and from liquidity/market-loss cover.

The clearest bridge-specific option: InsurAce

InsurAce has an explicit LI.FI Bridge Cover whose stated covered events include loss of tokens in transit resulting from bridge malfunction, hacks or vulnerability exploits, as well as certain errors in reported slippage. The coverage period runs from execution on the source chain through finalization on the destination chain.

That makes InsurAce particularly relevant if your exposure is “assets disappear or arrive short because the bridge/messaging path fails.” LI.FI also describes its earlier bridge-insurance product as providing protection against funds being lost while bridging.

Nexus Mutual: broader risk-transfer layer

Nexus Mutual currently offers cover for smart-contract exploits, oracle failures, governance attacks and liquidation failures, with eligibility depending on the particular listed protocol/cover. Its Multi Protocol Cover can span designated protocols across EVM-compatible and selected non-EVM chains.

For your liquidity-failure concern, Nexus is especially interesting where “liquidity failure” means a liquidation mechanism fails, markets freeze, or bad debt emerges. It explicitly identifies liquidation failure as a covered risk under several of its products.

The important caveat for a bridge operator is that this isn't automatically equivalent to “insurance against our bridge's liquidity pool becoming insufficient.” You'd need the actual listing/wording to establish that your particular liquidity shortfall is covered.

Sentora: worth investigating for bespoke institutional cover

Sentora's institutional platform explicitly says it arranges programmable cover for code-execution, economic, oracle and bridge risk, with cover registered onchain and settled programmatically.

For a bridge operator rather than an end user, this is potentially more interesting than a retail-style policy because you can investigate whether the risk can be structured around your actual bridge architecture and loss scenarios.

Sherlock: complementary rather than a liquidity insurer

Sherlock is primarily a Web3 security-review/risk platform. It has arrangements involving financial coverage/reimbursement, but explicitly says it is not an insurance company and that any financial protection is governed by the particular written terms.

So I'd view it as a security + exploit-risk-transfer component, not as the primary solution for a bridge liquidity shortfall.

What I'd put on your shortlist

For a firm operating bridges, I'd investigate these in roughly this order:

1. InsurAce — strongest match for bridge-specific exploit, malfunction and transfer-loss exposure.
2. Sentora — particularly worth approaching for bespoke institutional/programmable bridge and economic-risk coverage.
3. Nexus Mutual — strong candidate for a broader portfolio covering smart-contract, oracle, liquidation and related DeFi risks.
4. Sherlock — useful as a complementary security/exploit-risk layer rather than a standalone liquidity-failure insurer.

One distinction is critical in negotiating the policy: define liquidity failure precisely. “Bridge pool is drained by an exploit,” “LPs withdraw and the bridge cannot honor redemptions,” “destination-chain liquidity disappears,” “slippage exceeds X%,” and “market depeg causes a collateral shortfall” are materially different insurable events. Current products don't necessarily treat them interchangeably.

If you're evaluating this for an institutional bridge operator, I can also build a side-by-side matrix of coverage triggers, exclusions, limits/capacity, claims process, counterparty/capital model, and whether each provider will cover the bridge operator itself rather than its users.

Nexus Mutual: broader risk-transfer layer

Nexus Mutual currently offers cover for smart-contract exploits, oracle failures, governance attacks and liquidation failures, with eligibility depending on the particular listed protocol/cover. Its Multi Protocol Cover can span designated protocols across EVM-compatible and selected non-EVM chains.

For your liquidity-failure concern, Nexus is especially interesting where “liquidity failure” means a liquidation mechanism fails, markets freeze, or bad debt emerges. It explicitly identifies liquidation failure as a covered risk under several of its products.

The important caveat for a bridge operator is that this isn't automatically equivalent to “insurance against our bridge's liquidity pool becoming insufficient.” You'd need the actual listing/wording to establish that your particular liquidity shortfall is covered.

Sentora: worth investigating for bespoke institutional cover

Sentora's institutional platform explicitly says it arranges programmable cover for code-execution, economic, oracle and bridge risk, with cover registered onchain and settled programmatically.

For a bridge operator rather than an end user, this is potentially more interesting than a retail-style policy because you can investigate whether the risk can be structured around your actual bridge architecture and loss scenarios.

Sherlock: complementary rather than a liquidity insurer

Sherlock is primarily a Web3 security-review/risk platform. It has arrangements involving financial coverage/reimbursement, but explicitly says it is not an insurance company and that any financial protection is governed by the particular written terms.

So I'd view it as a security + exploit-risk-transfer component, not as the primary solution for a bridge liquidity shortfall.

What I'd put on your shortlist

For a firm operating bridges, I'd investigate these in roughly this order: