Diminished Value Claims: Getting Paid for Your Car's Lost Value

A diminished value claim asks an insurer to pay for the market value your car loses because it now has an accident history, even after it has been properly repaired. Given two otherwise identical cars, most buyers will pick the one that has never been in a wreck. You usually claim that difference from the at-fault driver’s insurer. Claiming it from your own insurer is much harder, and Georgia is the main state where courts have clearly required it.

The short version:

• Diminished value is the gap between your car’s market value before the accident and its value after repair (Washington Insurance Commissioner).
• You typically claim it from the at-fault driver’s insurer, not your own.
• Insurers do not pay it automatically. You have to prove the loss, often with an independent appraisal.
• In Georgia, courts have held that insurers owe it to their own policyholders too, after State Farm v. Mabry (2001).
• The “17c formula” came out of that Georgia case. It is one method, not a law, and it is widely criticised.

This is general information, not legal or insurance advice. Diminished value rules come from state court decisions and individual policies, and they vary a lot.

What diminished value means

When Georgia’s Supreme Court decided State Farm v. Mabry, it accepted the trial court’s finding that “the fact of physical damage resulting from an event covered by the policy can reduce the value of a vehicle, even if repairs return it to pre-loss condition in terms of appearance and function.”

A 2023 paper in the NAIC’s Journal of Insurance Regulation describes three kinds of diminished value:

• Parts-related: the car is worth less because inferior parts were used in the repair.
• Repair-related: the car is worth less because the repair work was poor.
• Inherent: the car is worth less simply because buyers know it was damaged, sometimes called “stigma”.

Parts-related and repair-related losses can be checked by inspecting the car. Inherent diminished value is the more subjective kind, and it is the one the paper focuses on.

Who you can claim from

Sources: Journal of Insurance Regulation; Washington Insurance Commissioner.

Third-party claims rest on ordinary damages law rather than on a policy. The Restatement of Torts, quoted in the Journal of Insurance Regulation paper, says damages for harm to property include the cost of repairs “with due allowance for any difference between the original value and the value after repairs.” The paper says many states allow it, including Florida, Georgia, Illinois, New York, and Virginia.

First-party claims depend on your policy wording. Regulators in Texas (Journal of Insurance Regulation) and South Dakota have said insurers do not owe their own policyholders diminished value when the car is fully repaired and the policy does not require it. South Dakota’s bulletin adds that this “does not alter the obligation to pay a third party claimant for a demonstrated loss of market value.” Insurers can also add a standard endorsement that excludes first-party diminished value, where the state allows it.

Georgia is the exception. The Journal of Insurance Regulation paper calls it the only state with clear legal direction that policyholders can recover diminished value from their own insurers. In Mabry, the court held that a policy promising to pay for your loss covers lost value, and that State Farm was “obligated to assess that element of loss along with the elements of physical damage when a policyholder makes a general claim of loss.” In other words, a Georgia policyholder does not have to ask separately.

If the at-fault driver is uninsured, your uninsured motorist coverage may include property damage; whether it pays diminished value varies.

How to file a diminished value claim

1. Finish the repairs and keep the paperwork. Keep the estimate, the final repair invoice, and photos of the damage before and after.
2. Get evidence of the lost value. The insurer pays only if you can show your car’s market value dropped even after repair (Washington Insurance Commissioner). Proving it may take a professional appraiser (Journal of Insurance Regulation). Listings for comparable cars and a dealer’s written trade-in opinion also help.
3. Send a demand letter. Write to the adjuster handling the at-fault driver’s claim. Give the claim number, your car’s value before the accident, its value after repair, the amount you want, and attach your evidence.
4. Negotiate. Expect a counter-offer or a denial. The Washington regulator warns that “an insurer may argue against it” and that you could end up needing legal advice.
5. Escalate if needed. Diminished value claims are often small enough for small claims court, according to the Journal of Insurance Regulation. Deadlines to sue for property damage vary by state, so check yours before talks drag on.

The 17c formula

The 17c formula comes from the Mabry litigation. The trial court gave State Farm several options, including what it called the “17(c) formula”, described as a “formula distributed by the Georgia Insurance Commissioner’s office and used by Safeco, Progressive, Nationwide and Crawford & Co.” State Farm chose it, and a later settlement order approved it for future Georgia claims. A 2021 federal court order in Baker v. State Farm describes how State Farm applies it:

1. Base loss of value: 10% of the car’s pre-loss retail value, as listed by the National Automobile Dealers Association (NADA).
2. Damage severity modifier: a number from 0.0 (“No structural damage and replaced panels”) to 1.0 (“Severe damage to the structure of the vehicle”). The NAIC paper gives 0.5 as the modifier for moderate damage.
3. Mileage modifier: (maximum miles minus actual miles) divided by maximum miles. The maximum is generally 100,000 miles, and for some vehicles 150,000.
4. Diminished value: base loss × damage modifier × mileage modifier.

Our diminished value calculator runs these steps for you.

A worked example. Say your car was worth $30,000 before the accident and had 40,000 miles on it, and the damage was rated moderate (0.5). The base loss is $3,000. The mileage modifier is (100,000 − 40,000) ÷ 100,000 = 0.6. The formula gives $3,000 × 0.5 × 0.6 = $900. The same car with 100,000 miles would get nothing.

Why the formula is criticised

In Baker, the policyholders’ appraiser argued that the formula always undervalues claims because:

• it caps diminished value at 10% of the car’s value, though he said cars can lose up to 25%;
• it counts mileage twice, once in the retail value and again in the mileage modifier;
• it treats cars over 100,000 or 150,000 miles as if they had no retail value, so they get nothing.

The Journal of Insurance Regulation paper adds that the formula involves no inspection of repair quality, and calls it “not sound and well-received.” The court in Baker was not persuaded that the formula undervalues every claim, and refused to certify a class action. It noted that policyholders who dislike the figure can present their own evidence and, if needed, take it to a jury. The NAIC paper’s broader point is that no standard formula for diminished value exists.

Frequently asked questions

Can I file a diminished value claim with my own insurance?

Usually only if your policy covers it. Georgia courts have held that insurers must assess and pay it on their own policyholders’ claims. Elsewhere it depends on your policy wording and your state’s court decisions, and many have said it is not owed once the car is fully repaired.

Can I claim diminished value if the accident was my fault?

Not from anyone else. Your only route is your own policy, which outside Georgia often will not pay it.

How much is a diminished value claim worth?

It depends on the car’s value, mileage, and damage, and on the evidence you bring. A claims adjuster quoted in the Journal of Insurance Regulation put typical settlements at 10% to 20% of the repair bill, but that is one person’s experience, not a rule.

Do I need an appraisal?

Not always, but you have to prove the value dropped. The Washington Insurance Commissioner notes that some owners make the claim themselves and others hire a company to document the lower value.

Is the 17c formula required by law?

No. It is a court-approved method from a Georgia class action, which State Farm uses in Georgia under court orders. Policyholders there can dispute the result with their own evidence.

Where to go from here

Gather your repair invoice and photos, get a valuation, and send your demand before your state’s deadline. See how a car accident settlement is worked out, how comparative negligence can reduce what you recover when fault is shared, how claims work in no-fault states, and when a car accident lawsuit becomes the next step. Arhox is an independent publication, not an insurer, broker, or law firm; our editorial policy and disclaimer explain how these guides are prepared.