Rate filing glossary

Published Oct. 6, 2026

These are the terms that come up most often in homeowners insurance rate filings and in our reports. Definitions are written by FiledRates. Where a regulator or the National Association of Insurance Commissioners (NAIC) describes the term, we link to that source.

Filing and review

Rate filing: A package an insurer submits to a state insurance regulator to set or change the rates it charges. It usually includes the proposed rates, the rating rules, and actuarial support explaining how the rates were calculated. Source: NAIC Product Filing Review Handbook, PDF page 7.
SERFF: The System for Electronic Rate and Form Filing, a web-based system run through the National Association of Insurance Commissioners that insurers use to submit rate, rule, and form filings to state regulators. Each filing gets a SERFF tracking number. Source: NAIC Product Filing Review Handbook, PDF page 7.
Prior approval: A rating system in which the insurer must file new rates and receive the regulator's approval before using them. Some states treat a filing as approved if the regulator does not act within a set number of days (see deemer provision). Source: NAIC Product Filing Review Handbook, PDF page 17.
File and use: A rating system in which an insurer may start using new rates when it files them. The regulator does not have to approve them first but can disapprove them later. Source: NAIC Product Filing Review Handbook, PDF page 17.
Use and file: A rating system in which an insurer may start using new rates and must file them with the regulator by a set later date. Source: NAIC Product Filing Review Handbook, PDF page 17.
Flex rating: A rating system in which a rate change needs the regulator's prior approval only if it is larger than a set percentage. Smaller changes can be filed and used without prior approval. Source: NAIC Product Filing Review Handbook, PDF page 17.
Deemer provision: A rule under which a filing is treated as approved if the regulator does not deny it within a specified number of days. Source: NAIC Product Filing Review Handbook, PDF page 17.
Disposition: The regulator's final action on a filing, such as approval, approval with changes, disapproval, or acknowledgment of a withdrawal. FiledRates records the date of that action as the disposition date.
Effective date: The date new rates start to apply. Filings often give separate dates for new policies and for renewals of existing policies.

Rates and how they are calculated

Overall average rate change: The single percentage an insurer reports as the average effect of a rate filing across all the policies it affects. Individual policyholders can see larger or smaller changes, or decreases, depending on their location, coverage, and other rating factors.
Rate indication: The rate change an insurer's actuarial analysis says is needed. Insurers often file for a change smaller or larger than the indication, so the indicated and requested changes can differ. Source: NAIC Product Filing Review Handbook, PDF page 26.
Base rate: The starting rate in a rating plan. The premium for a specific policy is calculated by applying rating factors, such as territory and coverage choices, to the base rate. Source: NAIC Product Filing Review Handbook, PDF page 33.
Territory: A geographic area an insurer uses as a rating factor. Rate filings often show different changes by territory. Source: NAIC Product Filing Review Handbook, PDF page 33.
Loss ratio: Losses an insurer incurred, expressed as a percentage of the premiums it earned over the same period. Source: NAIC Glossary of Insurance Terms.
Loss adjustment expense: The cost of investigating, settling, and recording claims, separate from the claim payments themselves. Often abbreviated LAE. Source: NAIC Glossary of Insurance Terms.
Loss trend: An adjustment that projects past claim costs forward to the period when new rates will apply, to account for inflation and other changes in how often claims happen and how much they cost. Source: NAIC Product Filing Review Handbook, PDF page 25.
Reinsurance: Insurance that an insurer buys from another insurer (a reinsurer) to cover part of its own losses. Some rate filings include the net cost of reinsurance as an expense. Source: NAIC Product Filing Review Handbook, PDF page 22.
Catastrophe model: A computer simulation that estimates potential losses from events such as hurricanes and earthquakes, based on insured property values, locations, and building vulnerability. Insurers use these models to set the catastrophe portion of rates. Source: NAIC Product Filing Review Handbook, PDF page 29.
Written premium: The total premium an insurer charges on policies it has written for their policy periods. Rate filings often state how much written premium the change affects. Source: NAIC Glossary of Insurance Terms.
Earned premium: The part of a prepaid premium that corresponds to the portion of the policy period that has already passed. Source: NAIC Glossary of Insurance Terms.
Underwriting: The process an insurer uses to decide whether to accept a risk, how to classify it, and what rate to charge. Source: NAIC Glossary of Insurance Terms.

Policies and markets

HO-3: The special form homeowners policy. It covers the house for all causes of loss except those the policy specifically excludes. It is the most common form in rate filings for owner-occupied homes. Source: Florida Department of Financial Services, Homeowners Insurance Overview.
HO-6: The condominium unit-owners policy. It primarily covers the owner's personal property and liability, with some coverage for the unit's structure. Source: Florida Department of Financial Services, Homeowners Insurance Overview.
HO-4: The renters policy. It covers a tenant's personal property and liability, not the building. Source: Florida Department of Financial Services, Homeowners Insurance Overview.
Deductible: The part of a covered loss, in dollars, that the policyholder pays before the insurer pays. Source: NAIC Glossary of Insurance Terms.
Residual market: Coverage arranged by a state for people who cannot get insurance through the regular market. State-created insurers of last resort, such as Florida's Citizens Property Insurance Corporation, are part of the residual market. Source: NAIC Glossary of Insurance Terms.