Rate Filing
Also known as: SERFF filing, rate/loss-cost filing
A rate filing is how insurance pricing becomes official. Before a carrier can charge a rate (or a bureau can publish an advisory loss cost), it files the proposed numbers and supporting actuarial justification with each state's Department of Insurance. Most states use SERFF (the System for Electronic Rate and Form Filing), and the non-confidential portions of filings are public record.
Filings come in a few flavors: base-rate / loss-cost filings (the per-class numbers), rate-change filings (an overall +/- percentage, e.g. 'a 6.9% workers'-comp decrease'), and form filings (policy language). A filing carries a tracking number (SERFF number), an effective date, and a status (pending, approved, withdrawn, superseded).
Because filings are regulator-held primary sources, they are the backbone of GBC's rate data — every figure in our state rate hubs and rate studies traces to a real filing. See the methodology page for how we capture and cite them.
Real-world scenario
Cedar & Pine Roofing, a 14-person residential roofer in Springfield, Missouri, buys workers' compensation on NCCI class code 5551 with an annual payroll of $850,000. Last year its carrier used a published loss cost of $8.50 per $100 of payroll and a loss cost multiplier of 1.42, producing a manual premium of roughly $102,595. After a rough claims year across the roofing class, the carrier submitted a rate filing to the state that raised its selected loss cost on 5551 to $9.75 per $100 — a 14.7% increase on that class.
When the filing took effect, Cedar & Pine's manual premium climbed to about $117,682 before any credits. Applying its experience modifier of 0.92 brought the modified premium to roughly $108,268 — up from about $94,387 the prior year (that term's $102,595 manual premium after the same 0.92 mod), a jump of nearly $13,881. The owner had budgeted only $105,000 for comp, so the increase forced a mid-year cash-flow adjustment. The carrier's filing package also carried a state filing fee of $250 and disclosed the underlying data — including a single fall-from-height claim that had reached a $185,000 incurred value, with $143,000 paid in indemnity and medical and about $42,000 in defense and legal costs.
Because Cedar & Pine carried a $1,000 per-claim deductible and a $1,000,000 employers-liability limit, the rate filing didn't change its coverage — only its price. Understanding that the number was driven by an approved, actuarially supported filing (not a whim) let the owner shop competing carriers whose own filings still showed a loss cost near $8.90, ultimately saving about $9,400 at renewal.
How it affects your premium
A rate filing itself isn't something a business "buys," but the numbers inside it directly set what you pay. These factors determine how a filing lands on your bill:
- Published loss cost by class — The advisory loss cost issued by a rate service organization (like NCCI or ISO) is the raw ingredient; a hazardous class filing moves your base rate far more than a clerical one.
- The insurer's loss cost multiplier — Each carrier files its own loss cost multiplier to cover expenses and profit, so two insurers using the same advisory loss cost can still quote very different premiums.
- Statewide loss and expense experience — Filings are supported by developed losses and trend data; a bad accident year in your class or state pushes the filed rate upward.
- Regulatory review type — Whether the state uses prior-approval or file-and-use rules changes how fast (and how much) a filed increase reaches you.
- Rate adequacy and profit load — Insurers file to hit a target rate adequacy and profit goal; underpriced books trigger corrective filings, while overpriced ones can produce filed decreases.
- Territory and schedule factors — Many filings include territorial relativities and schedule-rating rules that adjust the base rate for your specific location and risk features.
- Effective date and renewal timing — A filing approved by the department of insurance only hits your policy at your next renewal, so timing determines which filed rate you actually get.
Common misconceptions
Myth: My insurance company can raise my rate whenever it wants.
Reality: In most lines and states, an insurer must submit a rate filing to the regulator and either get approval or use it on file before charging the new rate. Whether it's fast or slow depends on the state's prior-approval vs. file-and-use system.
Myth: A rate filing tells me exactly what my premium will be.
Reality: A filing sets rates, relativities, and rules — not your final bill. Your actual premium comes from applying those filed rates to your specific exposure, mods, and credits, which is why rate is not the same as premium.
Myth: Rate filings only exist for big carriers and don't affect small businesses.
Reality: Every admitted insurer must file rates for standard lines, and those filings flow straight into what a two-person shop pays. Only excess and surplus lines carriers are generally exempt from filing rates.
Frequently asked questions
What exactly is a rate filing?
Does a rate filing decide my premium by itself?
Who reviews rate filings?
Can I see the rate filing that affected my premium?
Why did my rate go up if I had no claims?
Sources cited
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