Cell captives and protected cell companies: how renting a cell works

A cell captive, also called a rent-a-captive or protected cell captive, lets a business insure its own risks through a segregated account inside a licensed insurer owned by someone else, the sponsor. You get the core features of a captive, including a share of underwriting results and investment income, without forming and capitalizing your own captive insurance company. The cell's assets and liabilities are kept apart from every other participant's by statute. The catches are that you depend on the sponsor, the legal separation is only as strong as the domicile's law, and the tax result still depends on genuine risk distribution.

How a cell works

The NAIC's captive page describes a rental captive as one that offers captive benefits to policyholders or associations while insuring only their risks, and a protected cell captive as similar, with each user's assets legally protected from the others.

In practice:

1. A sponsor holds the license. The sponsor, often a captive manager, an insurer, a broker or an association, owns a sponsored captive insurance company approved by the domicile's regulator.
2. You sign a participation contract with the sponsor. In Vermont, 8 V.S.A. § 6034(8) says no participant contract takes effect without the Commissioner's prior written approval.
3. You fund a cell with capital and premium. The cell's income, expenses, assets, liabilities and capital are accounted for separately.
4. A fronting insurer issues the policy to your business if a licensed carrier is needed, and cedes the agreed share to the cell. See fronting arrangements and fronting carriers: how they work.
5. The cell pays claims from its own assets. Losses above the cell's retention are covered by reinsurance or excess coverage that you or the sponsor buys.
6. Results flow back to you as the cell builds surplus or, in a bad year, spends it. When the program ends, you are entitled to what is left after claims and expenses are settled, under the contract.

Types of cell structure

Vermont's 2025 aggregate report shows how widely cells are used. At December 31, 2025, Vermont had 67 active sponsored captives and 282 active or dormant cells (167 protected cells and 108 incorporated protected cells active, plus 7 dormant), 34 separate accounts, and 549 cells approved since the program began, 36 of them in 2025. Tennessee reported 703 cells in March 2026, with 50 new cells in 2025. Utah's captive director said in September 2026 that cells let smaller and mid-sized companies enter the market with less upfront capital, and Utah had licensed 19 new cell captives that year as of August 31, 2026.

What the law protects, and what it does not

The central promise of a cell is segregation. Under Vermont's statute, "the assets of a protected cell shall not be chargeable with liabilities arising out of any other insurance business" (8 V.S.A. § 6034(3)), and a creditor of one cell has no recourse against the assets of another (§ 6039(a)). In an insolvency, the Commissioner may separate cells from the sponsored captive, and solvent cells may be converted into new or existing companies (§ 6038).

That protection comes from a statute in the sponsor's domicile. The questions to put to a lawyer are whether the domicile's law is clear and tested, whether it holds if the sponsor itself fails or if a participant is in another state, and what a bankruptcy court would do with the cell's assets.

The sponsor's own financial position matters too. A sponsored captive must hold unimpaired paid-in capital and surplus of at least $100,000 before it issues policies in Vermont (8 V.S.A. § 6004(a)(6)), a threshold for the sponsor's general account, not a measure of how well it can stand behind your cell. Ask what the sponsor's capital, reinsurance and management depth actually are.

The tax test applies to cells too

A premium is deductible only if the arrangement is insurance for federal tax purposes. In Rev. Rul. 2008-8 (2008-5 I.R.B. 340), the IRS looked at a protected cell company in which each cell was funded by its participant and was walled off from the others:

• One participant, one cell. A cell that insured only its owner, with premiums paid out of the owner's own funds and no claims paid from any other cell, was likened to a parent and its wholly owned subsidiary. With no risk distribution, it was not insurance, and the owner could not deduct the payments.
• A participant with many subsidiaries. A cell that insured twelve subsidiaries of its owner, with none accounting for less than 5% or more than 15% of the risk, did qualify, because the premiums were pooled across the subsidiaries.

The ruling states that the same principles apply to a cell as to any other issuer. The practical lesson is that the wall that protects a cell from other cells' creditors is the same wall that can defeat risk distribution if you insure only yourself there. A cell needs enough independent risks, from your own operations or from a properly structured pool, to count as insurance. See single-parent vs group captives: which structure fits? for the same test applied to pure and group captives.

A cell can also be used with the small insurer election under section 831(b). If the structure is a micro-captive, the disclosure rules and court record in Micro-captives (831(b)) and the IRS: rules, red flags and reporting apply, and a tax adviser who is independent of the sponsor should review the facts first.

What it costs and what you give up

Budget for these without trusting any average:

• Capital contribution to the cell, sized by the sponsor and regulator to your retention.
• Rental and management fees to the sponsor, plus fronting fees, claims administration through a third-party administrator, actuarial and audit allocations, and premium taxes.
• Collateral if the fronting carrier requires a letter of credit or trust.
• Reinsurance premium above the cell's retention.

What you give up compared with owning a captive: control of governance, investment decisions and sometimes claims handling; the ability to customize policies freely; and ownership of the licensed insurer. In exchange, you avoid the cost of forming and running a separate company and can usually start sooner.

When a cell fits

• A business testing a captive before committing, which may later convert to its own company. Ask the sponsor what conversion costs and how reserves transfer.
• Programs with modest premium that cannot carry a pure captive's fixed costs.
• Employee benefit programs, such as stop-loss insurance layers, that fit a captive structure; see group captives for medical stop-loss: how employer health captives work.
• Associations or affinity programs that want each member's results kept separate.

It fits poorly when the business wants complete control, or when the main purpose is a tax deduction. Is a captive right for your business? A feasibility checklist covers the feasibility questions.

A hypothetical example

Say a regional distributor pays commercial carriers about $600,000 a year for general liability, auto liability and product liability, with five years of steady claims below $250,000 per occurrence. Forming a pure captive looks heavy for that size. The distributor rents a cell from a sponsored captive, funds it with the capital the sponsor requires, buys the policy through a fronting carrier and reinsures claims above $250,000. In a good year the cell builds surplus; in a bad one the cell spends it and the distributor may need to top it up. If the distributor later leaves, it recovers the cell's remaining assets only after open claims are settled and the contract's fees are paid. The numbers are invented to show the mechanism, not a quote.

Questions to ask a sponsor

1. Who is the sponsor, who regulates it, and what are its audited capital and management track record?
2. Is the cell a protected cell, an incorporated cell or a separate account, and what statute protects it?
3. What is the fee schedule, and which fees are fixed and which scale with premium?
4. Who controls investments, claims and reserves, and what reports do you receive?
5. What collateral is required, and when is it released?
6. What are the exit and conversion terms, and how long do you stay responsible for open claim years?
7. How will the program show risk distribution for tax purposes?

Key takeaways

• A cell captive lets a business use a captive structure without forming its own insurer; the sponsor holds the license and your cell is segregated by statute or contract.
• Segregation protects a cell from other cells' creditors only to the extent the domicile's law and the sponsor's compliance hold, so check the sponsor's financial strength and the legal basis.
• Under Rev. Rul. 2008-8, a cell insuring only its owner lacked risk distribution; a cell insuring many of its owner's subsidiaries did not.
• Cells are growing: Vermont reported 282 active or dormant cells at year-end 2025 and Tennessee 703 cells in March 2026.
• Compare fees, collateral, control and exit terms with a pure or group captive before choosing.