Uninsured and Underinsured Motorist Claims Explained

Not every at-fault driver carries enough insurance to cover what they caused — or any insurance at all. Uninsured and underinsured motorist coverage exists for exactly this gap, and understanding how it works changes both who you file against and how the claim is negotiated.

The Difference Between UM and UIM Coverage

Uninsured motorist (UM) coverage applies when the at-fault driver has no liability insurance at all, or flees the scene (a hit-and-run) and can’t be identified. Underinsured motorist (UIM) coverage applies when the at-fault driver has insurance, but their policy limit is too low to cover the full value of your damages. Both coverages are attached to your own auto policy, not the other driver’s.

Why You File the Claim With Your Own Insurer

This is the part that surprises most claimants: a UM/UIM claim is filed against your own insurance company, even though you did nothing wrong. Your insurer effectively steps into the shoes of the uninsured or underinsured driver and evaluates the claim much like a liability insurer would — reviewing medical records, applying a pain and suffering multiplier, and potentially disputing the value, even though they’re your own carrier.

How a UIM Claim Actually Works in Practice

1. You first pursue the at-fault driver’s liability policy and typically must exhaust their policy limit before your UIM coverage is triggered.
2. If your total damages exceed what the at-fault driver’s policy pays, you then file a UIM claim with your own insurer for the difference, up to your UIM policy limit.
3. Your insurer usually must be notified of the underlying claim and settlement before you finalize it, since accepting a settlement without notifying them can sometimes waive your right to pursue the UIM difference.

Is UM/UIM Coverage Required?

Requirements vary significantly by state. Some states mandate that insurers offer UM/UIM coverage and require drivers to reject it in writing if they don’t want it; others make it entirely optional. Given that a meaningful share of drivers carry only state-minimum liability limits or no insurance at all, UM/UIM is widely considered one of the more valuable optional coverages a driver can carry.

What a UM/UIM Claim Can Cover

• Medical expenses beyond what the at-fault driver’s policy pays.
• Lost wages — see our guide to calculating lost wages for how that figure is built.
• Pain and suffering, calculated the same way it would be in a standard third-party claim.
• In some states and policies, property damage as well, though this is less universal than injury coverage.

Common Friction Points With UM/UIM Claims

Because you’re negotiating against your own insurer rather than a stranger’s, it can feel adversarial in a way that catches people off guard — your insurer’s financial interest is still to pay as little as possible. The negotiation tactics involved are largely the same ones used in any liability claim; our guide on common adjuster tactics applies here just as much as it does to a third-party claim.

Frequently Asked Questions

This article is educational only and not legal or insurance advice. UM/UIM rules, requirements, and procedures vary by state and by policy — review your specific policy and consult a licensed professional.