Your own UM coverage, or a claim against the other driver
These are two different claims with different rules, different leverage and different procedures, and in a surprising number of cases you will run both at once.
Side by side
| Third-party claim | UM / UIM claim | |
|---|---|---|
| Against whom | The at-fault driver's insurer | Your own insurer |
| Legal basis | Negligence | Your insurance contract |
| Duty owed to you | None. They are adverse | Good faith and fair dealing, owed directly to you |
| Cooperation | You owe them nothing — no recorded statement required | Your policy's cooperation clause applies |
| Where disputes go | Court | Usually binding arbitration under the policy and Ins. Code § 11580.2 |
| Leverage beyond the limit | Bad faith exposure runs to their own insured, not to you | An unreasonable denial can expose your insurer to you directly |
| Limit | Their policy limit | Your UM limit, offset by what you recover from them in a UIM case |
When both run
In an underinsured case, the usual sequence is: settle with the at-fault driver for their limit, then pursue your own insurer for the difference up to your UIM limit.
Remember too that California UIM is offset rather than stacked: your insurer pays the difference between their limit and yours, not your full limit on top. If your UIM limit is no higher than theirs, there is no UIM claim.
The emotional part
People resist UM claims because it feels like turning on their own insurer, or like making a claim against themselves. Neither is accurate. You bought this coverage for precisely this situation, paid premiums for it, and the alternative is absorbing somebody else's failure to insure.
What is true is that the relationship changes once the number gets serious. The same company that was pleasant about the rental car is now the adverse party valuing your injury — and the arbitration it goes to is a genuine adversarial process.
Questions people ask
Will making a UM claim raise my premium?
Making a claim under coverage you paid for, for a collision you did not cause, is not an at-fault claim and should not be treated as one. If an insurer does treat it that way, that is worth challenging — and it is beside the point when the alternative is paying for someone else's uninsured driving yourself.
Do I need permission before settling with the other driver?
If you intend to make an underinsured motorist claim, yes — your own insurer's written consent. Accepting and signing a release without it can waive the UIM claim entirely.
Does a UM claim go to court?
Usually not. California UM and UIM disputes typically go to binding arbitration under the policy and Insurance Code section 11580.2, where an arbitrator decides both fault and damages.
Related
Reviewed October 2026 by Simon Aziz Budhwani, Esq., the attorney responsible for this site. Legal statements here name the California code section they rely on, so you can check them rather than trust them. This is information about the law in general, not advice about your situation.
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