How Much Capital Does a Captive Insurance Company Need?
The statutory minimum is the licence floor, not the answer. What actually sizes a captive's capital: the business plan, the regulator, and the premium-to-surplus yardstick.
The short answer: less than most people expect in order to get licensed, and more than the statute says in order to run well. In Vermont, the statutory minimum for a pure captive is $250,000 - but the figure a captive actually operates with is set by the Commissioner against its business plan, and prudence is judged with yardsticks such as the premium-to-surplus ratio. The minimum is a licence floor, not a capital plan.
The floor: statutory minimums
Every domicile sets a monetary floor. Vermont's tailored captive statute (8 V.S.A. ch. 141) puts it at $250,000 for a pure captive, with the Commissioner then setting additional capital based on the business plan. The pattern - a modest fixed floor plus regulator judgement - is the US captive model generally.
Regimes elsewhere are converging on the same shape. The UK's proposed captive framework (PRA consultation CP11/26, targeted at roughly 2027) would set a captive capital requirement at the higher of 10% of net written premium or 10% of net liabilities, with a £100,000 floor; the EU is keeping captives inside Solvency II's risk-based SCR and MCR while lightening the load for small undertakings. Both remain proposals or transitions rather than settled law, and the details are still moving.
The working answer: the business plan
Regulators do not license a number; they license a plan. The capital question they actually ask is whether this captive - these retained lines, this volatility, this reinsurance protection, this growth path - can absorb a bad year and still pay claims. Long-tail casualty lines with slow, uncertain development need more capital per dollar of premium than short-tail property. Generous reinsurance above the retention reduces the capital the captive itself must hold; ambitions to add lines or grow premium raise it. The actuarial projections in the feasibility study, not the statute, produce the number the regulator agrees to.
The yardstick: premium-to-surplus
The familiar prudence measure is the premium-to-surplus ratio. At 3:1, every $3 of premium written is backed by $1 of capital - a leverage dial, where a higher ratio means a thinner cushion. The NAIC's IRIS screens flag net premium-to-surplus above 300% as a warning sign, and the old Kenney rule treated 2:1 as genuinely conservative. So 3:1 is the regulator's eyebrow-raise line, not a target.
Sizing a mid-market casualty captive
A captive plans to write $6m of casualty premium. At a conservative 2:1 premium-to-surplus, that implies roughly $3m of capital; at 3:1, roughly $2m. The statutory floor might be $250,000 - but no regulator would license this plan at the floor, and no fronting carrier or reinsurer would treat it as adequately capitalised there.
What capital costs - and why sizing it is a design decision
Capital is not spent, but it is not free. Money committed to the captive is money the group cannot deploy elsewhere: at a 10% expected return, every $1m of capital locked in costs roughly $100,000 a year in foregone return, before letter-of-credit fees and administration. That is why capital efficiency shapes structure choices - cell facilities and quota-share reinsurance exist in part to do the same job with less trapped capital - and why over-capitalising is a real cost, not merely a conservative virtue.
A regulatory minimum is the least a captive can get away with, not what it needs. A low floor does not make a thin capital base safe - and the regulator, the fronting carrier and the reinsurance market will each apply their own, higher test.
Keep learning by email
Get new lessons, insights, and tools from Retained Academy in your inbox — free, unsubscribe at any time.