Casualty Actuarial and Statistical Task Force Discuss Cross Subsidization White Paper

The Casualty Actuarial and Statistical (C) Task Force continued its broad work on actuarial standards, statistical reporting, rate regulation, and homeowners-market issues at the 2026 Summer National Meeting. A principal topic of discussion was the exposed homeowners rate-regulation white paper addressing claims of cross-state catastrophe-loss subsidization.

The task force adopted its Spring National Meeting minutes and multiple interim meeting minutes, as well as several major reports at the meeting, including the 2024 Competition Database Report, the 2023 Dwelling Fire, Homeowners Owner-Occupied, and Homeowners Tenant and Condominium/Cooperative Unit Owner’s Insurance Report, and the Report on Profitability by Line by State.

The task force also adopted reports from the Actuarial Opinion (C) Working Group and the Statistical Data (C) Working Group, adopted a Title Schedule P Instructions proposal, and discussed Schedule P next steps. It also received updates on its 2026 charges and rate-filing review training.

Actuarial and Statistical Work

The Actuarial Opinion (C) Working Group released the 2026 P/C Regulatory Guidance for a 37-day public comment period ending Aug. 21. It also discussed prospective 2027 instructions for the P/C Statement of Actuarial Opinion, P/C Actuarial Opinion Summary, and Title Statement of Actuarial Opinion.

The Statistical Data (C) Working Group continued reviewing comments on multiple sections of the Statistical Handbook of Data Available to Insurance Regulators, including Sections 1, 2, 3, 5, 7, and 8.

CASTF also continued its regulator education series on predictive modeling. The “book club” sessions covered large –language model applications in claims analysis, entropy-based approaches to measuring statistical bias, artificial intelligence, and NAIC work involving the use of AI in reviewing pricing generalized linear models.

Rate Regulation White Paper

CASTF discussed comments on the exposed draft white paper, “U.S. Homeowners Insurance: Rate Regulation—A Regulatory Perspective.” The paper was developed under a 2026 charge from the Property and Casualty Insurance (C) Committee to explain state-based homeowners rate regulation, with particular attention to public and academic questions concerning cross-state subsidization of catastrophe losses.

The paper’s central conclusion is that homeowners rates are designed and reviewed to reflect the expected future cost of risk in the state where the policy is written, rather than to transfer one state’s catastrophe costs to policyholders in another state. It argues that cross-subsidization is constrained through state rate laws, actuarial standards, rate-filing review, market-conduct oversight, and competitive market forces.

The paper describes the familiar rating standard that rates must not be excessive, inadequate, or unfairly discriminatory. It explains that regulators review insurers’ data, assumptions, methods, catastrophe provisions, expense loads, reinsurance costs, and rating factors to determine whether a filing is adequately supported for the specific state.

Cross-Subsidization Analysis

The white paper defines structural cross-state subsidization as a market-wide condition in which policyholders in one state systematically pay inadequate rates for their own expected costs while policyholders in another state pay more than their expected costs to offset the difference. Under the paper’s approach, both conditions must be present: a meaningful market-wide distortion, and rates that are not actuarially justified in the affected states.

The paper distinguishes that concept from several circumstances that may create the appearance of cross-subsidization without establishing it, including:

• State-specific actuarial assumptions, credibility treatments, catastrophe loads, trends, expense allocations, and reinsurance strategies that may differ while remaining actuarially justified;
• Rate-filing timing and differences in filing requirements that can cause temporary variation between indicated and implemented rates;
• Changes in an insurer’s mix of business, growth strategy, or underwriting portfolio that can affect pricing decisions; and
• Broader economic conditions, including rebuilding-cost inflation, reinsurance pricing, and capital-market conditions, that can influence a state-specific rate filing without amounting to the transfer of losses from another state.

The paper also emphasizes that premiums are prospective estimates of the cost of risk transfer during a future policy period, not retrospective mechanisms for recovering prior catastrophe losses.

Industry Implications

The rate-regulation paper provides a useful regulatory framing for discussions about homeowners affordability, catastrophe exposure, and perceived interstate cost shifting. Its final form may become a reference point for regulators, legislators, the industry, and consumers.