Single-parent vs group captives: which structure fits?

A single-parent (pure) captive insures one owner and its affiliates. A group captive is owned by several unrelated businesses, usually in one industry, that pool a layer of their risk in one insurer. The single-parent structure gives you control and all of the result, but you supply the capital, bear the volatility and must show the IRS there is enough independent risk to count as insurance. A group captive lowers the entry cost and brings pooling built in, in exchange for less control and exposure to your co-members.

Both are forms of the captive explained in what is a captive insurance company and how does it work?. This guide is about choosing between them.

The two structures side by side

How the single-parent captive is judged

A pure captive concentrates the IRS's attention on one question: is anyone else's risk in the pool? The IRS answered with a set of revenue rulings, and the answers still anchor the planning.

• Parent insured alone: In Rev. Rul. 2005-40, an insurer covering one company, even through twelve disregarded single-member LLCs of that company, did not provide insurance. The same insurer covering twelve LLCs taxed as separate associations did.
• Parent plus outside business: In Rev. Rul. 2002-89, a subsidiary that took 90% of its premium from its parent was not insurance; one that took under 50% from the parent was.
• Sister subsidiaries: In Rev. Rul. 2002-90, an insurance subsidiary covering twelve professional-service subsidiaries, each accounting for between 5% and 15% of the risk, was insurance.

Courts have been less rigid than the revenue rulings. In Rent-A-Center, Inc. v. Commissioner, 142 T.C. 1 (2014), the Tax Court held that a captive insuring only its parent's subsidiaries achieved risk distribution because those subsidiaries operated thousands of stores, vehicles and employees. A court looks at the number of independent exposures, not only the number of legal entities. But the facts matter, and the IRS has not stopped challenging structures. A pure captive with a handful of entities and modest exposure should expect to need third-party business, a reinsurance pool or a group structure to build credible distribution.

How a group captive works

Group captives come in several forms. Vermont's captive statute, 8 V.S.A. § 6001, defines an association captive as one that insures the risks of an association's member organizations, and an industrial insured captive as one that insures an industrial insured group. An industrial insured, in Vermont, must have a full-time employee acting as insurance manager or buyer, at least $25,000 of annual premium and at least 25 full-time employees. Other states use different definitions, and the term "group captive" in practice covers all of these.

A typical member-owned program works like this:

1. Each member buys in with a capital contribution, sized by the program.
2. Each member buys its liability, workers' compensation or auto coverage through the captive's fronting carrier, which cedes a layer to the group captive. Losses above the captive's layer are ceded to reinsurance markets.
3. Premium is priced using actuarial rates and adjusted for each member's experience, so safer members pay less over time.
4. Members post collateral, often a letter of credit, to the fronting carrier to back their share of expected losses.
5. Underwriting profit and investment income are returned as dividends, or accumulated in the captive, depending on the program's rules.

The IRS's reference ruling for this arrangement is Rev. Rul. 2002-91. Its facts are specific: a group captive formed by a significant number of unrelated businesses, no member owning more than 15% of the captive, holding more than 15% of any vote, or accounting for more than 15% of the risk insured; premiums pooled in general funds; no member owing extra premium if its losses ran high; and no refund if they ran low. That ruling treated the captive as an insurer and the premiums as deductible.

Real programs often add features that the ruling does not mention, such as loss-sensitive dividends, member-specific accounts and assessment rights. The more a program resembles each member funding its own losses through a separate account, the weaker the pooling argument becomes, because courts have said a policyholder should not be paying for its own risk in significant part. How a particular program handles that is a question for tax counsel before you sign, not for the sales presentation.

Where each structure is used

Group captives are common for lines where a trade has steady, similar exposure and wants stability: workers' compensation, auto liability and general liability for Trucking company insurance and General contractor insurance, and medical stop-loss for employers that self-fund health benefits (see group captives for medical stop-loss: how employer health captives work). Pure captives dominate the numbers. Vermont's 2025 aggregate report shows 477 of its 707 licensed captives were pure captives, against 14 association captives and 17 industrial insured captives, with 82 risk retention groups and 72 sponsored captives making up much of the rest.

Liability-only groups of one industry can also form a risk retention group, which has its own federal rules. Businesses that want captive economics without forming a company can rent a cell; see cell captives and protected cell companies: how renting a cell works.

Questions to ask before joining a group captive

• Who are the other members? Ask for the membership standards, the current member count and the industry mix. The pool is only as good as its worst underwriting decision.
• How is premium set and adjusted? Ask for the rate filing basis, the experience-rating formula and how much of your premium is pooled versus tracked to your own account.
• What is the maximum I can lose? Ask whether members can be assessed beyond the original premium and collateral.
• What collateral is required and when is it released? Letters of credit can tie up borrowing capacity for the life of the longest-tailed claim.
• Who adjusts claims and who controls settlements? A shared third-party administrator is common, and members usually have little say on others' claims.
• What happens when I leave? Find out how your reserves are valued, what dividend you forgo and how long you remain liable for open years.
• What do I get on loss control? Good programs require members to meet safety standards and share data, and that is where the savings come from.
• Where is it domiciled and who audits it? Ask for the audited statements and the most recent regulator exam, not a marketing summary.

A hypothetical choice

Say three mid-sized contractors each pay about $700,000 a year for workers' compensation and general liability. None has enough loss history to fill a $500,000 per-claim layer, and one bad claim would dominate any one captive's year. A pure captive would require each to fund full capital and absorb that volatility alone. A group captive spreads the first layer across all three, plus other members, with a shared reinsurance program above it. The trade-off is that each contractor accepts the group's underwriting, claims philosophy and exit terms. These numbers are invented to show the choice, not market prices.

If instead a national retailer with hundreds of locations and a decade of stable claims in several lines is considering a captive, a pure structure may fit, because its own exposure base is wide and it wants control over claims and data. The feasibility questions in Is a captive right for your business? A feasibility checklist should be answered first, and the domicile choice in Captive domiciles compared: Vermont, Utah, Delaware and offshore comes next.

Key takeaways

• A single-parent captive gives you control and the full underwriting result, but you carry the volatility and must support risk distribution on your own.
• A group captive pools unrelated members, so entry is cheaper and distribution is easier, but you share control and depend on the other members.
• The IRS rulings treat a captive as insurance when enough independent risk sits in the pool; Rev. Rul. 2002-91 describes a group captive with no member above 15%.
• Read the participation agreement for assessments, collateral, dividends and exit terms before you commit, and have tax counsel review the structure.
• A captive is a retention strategy, so decide first how much loss your balance sheet can absorb.