Short answer: After a crash, collision or comprehensive repairs often use sheet-metal or plastic exterior parts. OEM parts come from the vehicle’s original manufacturer (or its supplier channel). Aftermarket / non-OEM parts come from other makers. The NAIC After Market Parts Model Regulation (Model 891) says an insurer should not require aftermarket parts unless they are at least equal in kind and quality (fit, quality, performance), that parts must be identified, and that estimates using non-original parts must carry a written disclosure in at least 10-point type. State rules vary: Mississippi’s insurance department explains Non-OEM disclosure and that you may refuse a Non-OEM part but may have to pay the price difference; Texas Insurance Code §1952.301 generally bars insurers from specifying the brand, type, vendor or condition of parts (or limiting your choice of repair shop) except as commissioner rules allow.
This guide is national context with verified regulatory examples — not a 50-state table. Distinct from auto repair shop choice laws by state (who picks the body shop) and zero-deductible auto glass laws by state (glass-specific rules). Read your policy, the estimate, and your state insurance department’s claim pages before authorizing work.
OEM, aftermarket, and what Model 891 means by “after market part”
NAIC Model Regulation 891 defines an after market part, for purposes of that model, as sheet metal or plastic parts that generally constitute the exterior of a motor vehicle, including inner and outer panels, and defines a non-original manufacturer as a manufacturer other than the original manufacturer of the part (NAIC Model 891). The model’s purpose is prompt, fair settlement standards for insurer-paid repairs that use those parts, including disclosure when a non-original manufacturer part is proposed and a requirement that covered aftermarket parts be identified and of the same quality as the original (NAIC Model 891).
Identification. An aftermarket part subject to the model and made after its effective date must carry sufficient permanent identification of its manufacturer, accessible to the extent possible after installation (NAIC Model 891).
Like kind and quality. An insurer shall not require aftermarket parts unless the part is at least equal in kind and quality to the original part in fit, quality and performance, and insurers specifying aftermarket parts shall consider the cost of any modifications needed to make the repair (NAIC Model 891).
Disclosure. The insurer must disclose in writing, on the estimate or an attached document, in type no smaller than 10 point, language stating that the estimate is based on automobile parts not made by the original manufacturer and that such parts are required to be at least equal in kind and quality in fit, quality and performance to the OEM parts they replace. All aftermarket parts installed must be clearly identified on the repair estimate (NAIC Model 891).
States adopt or adapt Model 891 differently. Always check your own DOI or statute; the model itself is not automatically law everywhere.
Mississippi example: AMP vs Non-OEM and the right to decline
The Mississippi Insurance Department’s automobile physical-damage claims page distinguishes:
- AMP (as Mississippi describes it): replacements for non-mechanical sheet metal or plastic exterior parts that are manufactured by the car manufacturer. MID says there is no statutory requirement that use of those parts be disclosed to the insured in the way Non-OEM parts are (Mississippi DOI).
- Non-OEM / “competitive” parts: aftermarket crash parts made by a manufacturer other than the original vehicle manufacturer or its supplier. Each part must have the manufacturer’s logo, identification number or name affixed or inscribed; and if the insurer’s estimate uses Non-OEM parts, the written estimate from the insurer and repair facility must clearly identify each part and include the disclosure statement required by Mississippi Code (Mississippi DOI).
MID also states that a policyholder is not required to accept a Non-OEM part but may be required to make up the difference in price (Mississippi DOI). Separately, Mississippi law does not allow an insurer to condition payment on using a particular repair facility, though the insurer may recommend a shop (Mississippi DOI).
Texas example: no specifying brand or shop (with a commissioner-rules caveat)
Texas Insurance Code §1952.301 provides that, except as provided by commissioner rules, an auto policy delivered or renewed in Texas may not limit coverage by (1) specifying the brand, type, kind, age, vendor, supplier or condition of parts or products that may be used to repair the vehicle, or (2) limiting the beneficiary from selecting a repair person or facility. In settling a third-party liability property-damage claim, an insurer likewise may not require a particular shop or a particular brand/type/vendor/condition of parts (Tex. Ins. Code §1952.301). That is a parts-and-shop choice rule; it sits alongside the practical question of what amount the insurer will pay as a reasonable repair under the policy (TDI auto guide).
What collision and comprehensive actually pay
Collision pays for damage to your car from a crash with another car, an object, or overturning, subject to your deductible; comprehensive covers many non-collision physical-damage perils (theft, vandalism, weather, animal strikes, and similar, depending on the form) (NAIC; TDI). Neither coverage obligates the insurer to buy every OEM cosmetic panel at list price if the policy and state law allow like-kind-and-quality alternatives — but disclosure and quality rules (where adopted) still apply.
Questions to ask before the shop starts work
- Which parts on the estimate are OEM, recycled/OEM-used, or Non-OEM aftermarket — and are they named on the estimate?
- Is the Model-891-style (or state) disclosure attached if Non-OEM parts are specified?
- Who warrants fit and finish — insurer, shop, or parts maker — and for how long?
- Will ADAS calibration, structural procedures or OEM repair procedures be followed where required for safety?
- If you insist on OEM, what out-of-pocket difference applies?
Related reading: auto repair shop choice laws by state, total loss car valuation rules by state, catalytic converter theft and comprehensive, and the state insurance rules hub.
Frequently asked questions
What is an “after market part” under the NAIC model?
For Model 891, it means sheet metal or plastic parts that generally make up the exterior of a motor vehicle, including inner and outer panels — not every mechanical component under the hood (NAIC Model 891).
Can my insurer require cheaper Non-OEM fenders?
Under Model 891’s like-kind-and-quality rule, an insurer should not require aftermarket parts unless they at least equal the original in fit, quality and performance, and the estimate must disclose Non-OEM use. Your state may have adopted a version of that rule — or a different rule, such as Texas’s limit on specifying brand/vendor (NAIC Model 891; Tex. Ins. Code §1952.301).
Do I have to accept aftermarket parts in Mississippi?
Mississippi’s DOI says you are not required to accept a Non-OEM part but may have to pay the price difference, and Non-OEM parts on an estimate must be identified with the statutory disclosure (Mississippi DOI).
Is choosing my own body shop the same issue as OEM vs aftermarket?
No. Shop-choice laws address whether the insurer can steer you to a particular facility. Parts rules address which replacement panels may be specified and what must be disclosed. See shop choice laws by state and this page together.
Will insisting on OEM parts increase what I owe?
Sometimes. If the insurer’s obligation is the reasonable cost of a like-kind-and-quality repair and you choose more expensive OEM parts, you may pay the difference — as Mississippi’s DOI notes for Non-OEM refusals. Confirm in writing before work begins (Mississippi DOI; TDI).
Alishahi Insurance · 439 N Canon Dr, Penthouse, Beverly Hills, CA 90210 · (877) 711-4545 · CA License #4348151. General information only. This isn't legal, tax or financial advice or a coverage determination. Coverage depends on policy language and underwriting, and rules vary by state.