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Reading a rate filing to see how big a discount really is
Where insurers' filed rules and factor tables are public, how to find them, and how to convert a factor like 0.90 into dollars on the coverages it touches.
An insurer's advertisement says "save up to 25 percent"; its filed rating rules say exactly what each discount is worth, coverage by coverage. In many states you can read those rules yourself, free, in the state's public filing system. The skill is knowing which pages matter: the rule that defines the discount, the factor table that gives its size, and the rate pages that show the dollar base the factor multiplies.
Two cautions up front. A filing shows the formula, not your price, because your price also depends on your territory, your tier and facts the filing cannot know about you. And some documents in a filing are confidential and do not appear to the public. Within those limits, a filing is the best evidence available of what a discount is actually worth.
Why the filing is the source of truth
U.S. insurance is regulated state by state, and an insurer that sells personal auto in a state files the rules and rates it will use there with that state's insurance department. The Insurance Research Council reported in November 2024 that personal auto insurers submitted roughly 10,200 rate filings a year between 2010 and 2023, which gives a sense of how constantly these documents change.
The filing is the document the insurer is bound by. If the filed rule says a good student discount is a factor of 0.88 on liability and collision, the insurer cannot, in a state where the filing governs, charge you as though it were 0.95 without a new filing. A marketing page has no such force. State Farm's discount page, checked in November 2026, says its good student discount is "up to 25%" and that discounts vary by state; Progressive's says potential savings will vary and its figures are national averages. Both statements are accurate. Neither tells you what the discount is worth in your state, on your coverages, at your age and grade level. The filing does.
Our guide on how rate approval works explains the review process, and loss ratios and rate filings explains why insurers file changes. This article is about reading the output.
Where to find a filing
Most states publish filings through SERFF Filing Access, a public interface built on the NAIC's System for Electronic Rate and Form Filing, or through their own search page. Three state pages show how it works.
- Texas. The Texas Department of Insurance has a consumer page on home and auto rate filings. It says insurers must file their rates with the department before using them to set premiums, and that you search by the company name, which you can find on your policy or billing statement, not the agency's name. Results show the received date, the type of insurance, a product name, the estimated percent change for existing policyholders, a SERFF filing number, separate effective dates for new business and renewals, and a status of pending or closed. The page warns that documents marked confidential will not appear. TDI's October 8, 2026 news release shows the kind of activity you will find: it reported that companies had filed auto rate decreases affecting 4.4 million policyholders since July 1, 2026, including a 10.3 percent decrease filed by Loya Insurance Company (TDI release).
- Indiana. The Indiana Department of Insurance says insurer filings submitted electronically to it are available through SERFF Filing Access at no cost, and that original filings can be viewed by appointment.
- Delaware. The department says company filings are available to the public through the NAIC's SERFF interface with no fee, and points to its rate division for help finding a filing.
Not every state is this open, and what is marked public varies. If your state's department of insurance does not offer a search, call or write to the rate division and ask how the public can obtain the rating rules for a named company.
A search routine
- Get the exact legal name of your insurer from the declarations page. Large groups file under several company names (a "Mutual", a "Casualty", a "Fire and Casualty"). The one on your policy is the one that matters.
- Search by that name in your state's system, and filter for private passenger auto if the tool allows.
- Read the list columns. The status, the effective dates for new business versus renewals, and the percent change tell you which filing is currently in use. A Texas result with a blank or zero percent change, TDI says, means only rules or something else with no premium effect changed, which can still be the filing that changes a discount rule.
- Open the filing with the most recent effective date that has closed or been approved. A pending filing may not be in use yet.
- Find the rate and rule documents, usually in the filing's rate and rule schedule section, and open the PDF attachments.
- Save the document and note the filing number and the effective date. You will want to cite it if you ask the insurer a question.
Anatomy of a filing: rules, rates and support
Filing formats differ among insurers and states, but most contain three kinds of document.
| Document | What it holds | What you use it for |
|---|---|---|
| Rules manual | Text rules: who qualifies for each discount, how to apply it, in what order, what proof is needed | Eligibility and combination rules |
| Rate pages and factor tables | Base rates by coverage and territory; factors for class, vehicle, deductible and discounts | The size of each discount |
| Supporting documentation | Actuarial memorandum, loss experience, the requested change | Why the change was filed and how large it is overall |
Discount sizes can sit in either the rules or the tables. Some insurers print the percentage in the rule ("a 10 percent discount applies to…"). Others put the rule in words and the number in a separate table of factors. If you can find the rule but not the number, look for a table named for the discount, or for "miscellaneous factors" or "policy factors."
Reading a real factor table
An example is more useful than a description. The Commonwealth Automobile Reinsurers (CAR) publishes the rating manual for the Massachusetts private passenger residual market, the assigned-risk pool. It is public on the CAR website. The version dated July 1, 2026, has a page headed "Miscellaneous Rating Factors." This is the residual market and not a typical insurer's voluntary-market filing, so treat it as an illustration of the format. A voluntary insurer's pages will have different numbers and layouts.
Under the heading "Discounts (Rule 19)" the page lists, in substance:
- Annual mileage: 0 to 5,000 miles, 10 percent, applying to "Parts 1-8 and 12"; 5,001 to 7,500 miles, 5 percent, same parts.
- Multi-car: 5 percent, applying to Parts 1, 2, 4, 5, 7, 8 and 9.
- Continuous coverage: 10 percent, Parts 1, 2, 4 and 5.
- Low frequency: 10 percent, Parts 1, 2, 4 and 5.
Three lessons come directly from that page.
First, every discount is tied to named coverage parts. The mileage discount touches Parts 1 through 8 and 12. The multi-car discount touches seven parts and skips others. The two behavior-based discounts touch four. The part numbers appear to refer to the numbered coverage parts of the Massachusetts policy, which the manual defines elsewhere; the page itself does not name them. A single percentage printed in an advertisement collapses all this.
Second, the page also shows how other adjustments are expressed. In the same July 1, 2026 table, the collision deductible factors are written as multipliers relative to a $500 deductible at 1.00: $1,000 is .80 and $2,000 is .66. A footnote adds that the collision waiver-of-deductible factor is added to the collision deductible factor, which is an additive step inside a multiplicative table. Plans mix both methods, as the companion article on how discounts stack describes.
Third, the rule text is separate from the table. The table gives sizes; "Rule 19" gives the conditions, the order of application and the proof. You need both.
Turning a factor into a percentage and then into dollars
A factor is a multiplier. Subtract it from 1 to get the percentage change.
| Factor | Meaning | Percent change |
|---|---|---|
| 0.90 | Multiply the charge by 0.90 | 10% lower |
| 0.95 | Multiply the charge by 0.95 | 5% lower |
| 0.80 | Multiply the charge by 0.80 | 20% lower |
| 1.00 | No change | 0% |
| 1.25 | Multiply the charge by 1.25 | 25% higher (a surcharge) |
The dollar value depends on the charge being multiplied. Here is a hypothetical example, using the sort of structure the CAR page shows but with invented base rates.
Say a filed rate page gives a base collision charge of $520 a year for your territory and vehicle class at a $500 deductible.
- Deductible factor. You choose a $1,000 deductible, factor .80: $520 x 0.80 = $416.00.
- Multi-car discount. A 5 percent discount, factor 0.95: $416.00 x 0.95 = $395.20.
- Mileage discount. Say you drive under 5,000 miles a year and the filing gives 10 percent, factor 0.90: $395.20 x 0.90 = $355.68.
Collision falls from $520 to about $356, a 31.6 percent reduction on this coverage, from a 20 percent deductible factor and two discounts that total 15 percent if added. That is the same stacking logic as in the companion piece: percentages multiply, and you are reading the multiplication in the filing's own words.
Next, check the same discount on a different coverage. If the filing applies the mileage discount to liability but only the multi-car discount to comprehensive, the savings on each differ. For this reason, write down one line per coverage as you read, with the coverage, the base charge, each factor that applies, and the result. The car insurance quote comparison worksheet works as a layout.
Territory and tier change the dollars, not the factor
Two drivers with the same 0.90 factor can see very different savings. The factor multiplies a base charge, and the base charge varies by rating territory and, in some insurers' plans, by tier or company placement.
| Territory A | Territory B | |
|---|---|---|
| Filed base charge for a coverage | $400 | $900 |
| After a 0.90 discount factor | $360 | $810 |
| Dollar value of the discount | $40 | $90 |
The percentage is identical; the benefit more than doubles. This is why a friend in another city who "saved 15 percent" cannot tell you what you will save, and why a table from one market can only illustrate the format.
What the "up to" number corresponds to
The advertised ceiling often matches the largest factor in a table, applied to the group that earns it. A good student discount of "up to 25 percent" may correspond to a table in which the largest reduction applies to one age band, one grade level and one coverage, with smaller reductions for others. The filing lets you test that: find the table, look at the row for your age and grade category, and read your factor. If the rule says the factor is lower for some states or program versions, the footnotes in the insurer's own marketing, such as State Farm's note that Drive Safe & Save discounts vary by state and are capped at 30 percent in New York, are consistent with that. Our guide to car insurance discounts lists what each common discount requires.
Prior approval and file-and-use: what each lets you see
How much you can learn also depends on how the state reviews filings. In a prior approval state the insurer files and waits for the regulator to approve or disapprove before it uses the change. In a file-and-use state the insurer can start using the change on or soon after filing, and the regulator reviews it afterward. Some states use variations of each.
Consequences for a reader:
- Prior approval filings tend to sit pending for a period and carry the regulator's questions and the insurer's answers, which can be informative. California is the best-known case: Proposition 103 requires prior approval of rates, and the Insurance Code deems a filing approved 60 days after public notice unless a hearing is held, with hearings required on request for personal-lines changes over 7 percent. See California Proposition 103 explained.
- File-and-use filings may already be in force when you find them, so check the effective date and whether a later filing superseded it.
- In both systems a closed filing is a record of what was filed, not proof it was applied to you. The status column and effective dates tell you which filing governed on your renewal date.
The limits of the exercise
A filing will not answer every question. Plan for these gaps.
- Underwriting tiers and company placement. Many insurance groups have several companies and tiers with different base rates. The filing may show the tiers, but the rules for which tier you are placed in may be in underwriting guidelines that are not public or are marked confidential.
- Confidential material. The Texas page warns that documents marked confidential are not shown. Insurers often claim confidentiality for scoring models and some supporting data.
- Volume and format. A filing may run to hundreds of pages in PDFs of varying quality. Searching within the document for the discount's name or "Rule" followed by the number usually finds it.
- Time. The filing in force when you bought may not be the one in force at renewal. Match the effective date to your policy period.
- Rules versus practice. The filing says what the rules are. It does not tell you whether your agent entered your information correctly, which is a job for the checks in auditing your policy for missed discounts.
- Interpretation. Rate manuals are written for actuaries and underwriters. If a rule is unclear, ask the insurer to explain it in writing, or ask the state department of insurance's consumer line.
Common questions
Is it legal for me to look at an insurer's rate filing?
Yes, where the state has made the filing public. The Texas, Indiana and Delaware pages above say public filings are available without a fee. Filings or parts of filings marked confidential are not shown.
Can I find the exact price I will pay in a filing?
No. A filing gives the formula and its inputs. Your price also depends on your driving record, vehicle, territory, tier, coverage limits and the data the insurer pulls on you. Use the filing to understand the discounts, and the quote to get the price.
Why can't I find a filing for my insurer?
Check the legal name on your declarations page; groups file under several names. Check that you are searching the right state, the right line of insurance (private passenger auto) and a date range that includes your policy period. If the state has no public search, ask the rate division how to request it.
What does a "percent change" on the filing list mean?
In Texas, it is the estimated effect of the filing on existing policyholders' premiums, and a blank or zero means the filing changed rules or other items without a premium effect, or that the overall effect is zero. A positive figure is an average across policyholders, not the change you will see.
Does a bigger discount factor always mean a cheaper policy?
No. A company with a high base rate and a generous discount can cost more than one with a low base rate and a modest discount. Compare final quotes for the same coverage, and use the filing to understand why they differ.
Key takeaways
- Marketing gives a ceiling; the filed rules and factor tables give the size of each discount, by coverage.
- Search your state's public filing system by the insurer's exact legal name, and match the effective date to your policy period.
- Convert a factor to a percentage by subtracting from 1, then multiply by the base charge of each coverage the discount applies to.
- The same factor is worth different dollars in different territories and tiers, so a filing explains the mechanism, not your personal saving.
- Tiers, company placement and confidential exhibits limit what a filing shows; confirm questions with the insurer in writing.