When your vehicle is repaired after an accident, even an excellent repair leaves the car worth less on the open market than an identical unaccidented car. This reduction in resale value is called diminution in value — and in many situations, it is a real, compensable loss that policyholders rarely know to claim.
Diminution in value (DIV) is the difference between your vehicle's fair market value before the accident and its fair market value after repair. A buyer will pay less for a vehicle with an accident history — even a perfectly repaired one. Carfax reports, dealer appraisals, and market research consistently show this.
Third-party DIV applies when you seek compensation from the at-fault driver's liability insurer — a component of your total damages. First-party DIV arises from your own collision coverage — and this is where the law varies significantly by state. Some states recognize first-party DIV; others have interpreted collision coverage as covering only repair costs.
DIV is typically calculated using the comparable sales approach, a dealer appraisal method, or an appraiser's professional valuation. Document with written evidence — printouts from valuation tools, written dealer appraisals, and the vehicle's pre-accident value from sources like Kelley Blue Book or NADA.
To pursue a DIV claim: document your vehicle's pre-accident value immediately after the accident; obtain a professional appraisal of post-repair value; present your calculation to the insurer in writing; and if the claim is denied, escalate through the insurer's dispute process.
The Insurance Professor is trained on Illinois insurance law and regulation. Ask about your policy, your claim, or your rights.
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Regulatory resource: Illinois Department of Insurance — https://insurance.illinois.gov. The Insurance Professor provides education only — not legal or insurance advice.