Claim command center

UM/UIM Claim Documents Guide: Stack Limits, Medical Bills, and Carrier Coordination

A 6-step auto insurance claim playbook with a 8-item document checklist, plus denial and delay patterns to avoid before you file.

Reviewed by

Sarah Mitchell(Claims Documentation & Settlement Research Editor)Last reviewed: 2026-08-18Published: 2026-08-18Last updated: 2026-08-18Insurhi Rating Framework (IRF) · Editorial methodology

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Playbook brief

Prepare · File · Follow up

Steps: 6
Documents: 8
Denial patterns: 5
Read time: 4 min

Start here

First actions from this playbook

Confirm whether you are pursuing the at-fault carrier, your UM/UIM coverage, or both—and in what order your state allows stacking.
File FNOL with your carrier even if the other driver is liable; note you are preserving UM/UIM rights.
Gather the police report, all driver insurance cards, and witness statements before the first adjuster call.

Phase 01 · Workflow

Claim roadmap

Follow the CMS-verified steps in order and keep a written record as you progress.

1
Confirm whether you are pursuing the at-fault carrier, your UM/UIM coverage, or both—and in what order your state allows stacking.
2
File FNOL with your carrier even if the other driver is liable; note you are preserving UM/UIM rights.
3
Gather the police report, all driver insurance cards, and witness statements before the first adjuster call.
4
Submit medical bills and wage loss documentation as you receive them—do not wait for treatment to finish.
5
Track each carrier's reserve letters and coverage position in writing.
6
Before accepting any settlement, confirm whether signing a release affects UM/UIM recovery.

Phase 02 · Preparation

Document checklist

Gather these before filing to reduce back-and-forth with the adjuster.

Police report and incident number
At-fault driver insurance policy and claim number
Your declarations page showing UM/UIM limits
Medical records and itemized bills with CPT codes
Pay stubs or employer letter for wage loss
Photos of all vehicles and visible injuries
Witness names and written statements
Correspondence showing other carrier's liability acceptance or denial

Risk watchlist

Common reasons claims get denied

These show up most often in adjuster decisions for this claim type. Knowing them in advance usually changes how you document the loss.

UM/UIM not purchased or limits rejected in writing

Some states require signed UM/UIM rejections. Pull your declarations page and any signed selection forms.

Injuries deemed below the tort threshold

No-fault states may require serious injury thresholds before UM/UIM pays pain-and-suffering.

Settled with at-fault carrier without carrier consent

Your UM/UIM insurer may require approval before you release the other driver.

Household vehicle not listed on policy

UM/UIM may not extend to unlisted drivers or excluded household members.

Late notice to UM/UIM carrier

File with your carrier promptly even while the liability investigation continues.

Timeline

What slows a claim down

Most delays come from these causes — often fixable with a single phone call or follow-up email.

Liability investigation between two carriers

Expect 30–60 days when fault is disputed; keep treating and documenting.

Medical lien negotiations

Providers may wait for carrier letters before releasing records.

UIM arbitration clauses

Some policies require arbitration before suit—check your policy jacket.

Be ready

Supplemental documents you may be asked for

Adjusters routinely request additional records during review. Being ready keeps a claim from stalling.

Underinsured driver with minimal limits

Copy of at-fault policy declarations showing exhausted limits and your UIM declaration page.

Hit-and-run UM claim

Any witness statements, camera footage requests, and UM police report supplement forms.

Escalation

If your claim is denied, delayed, or short-paid

Concrete next steps for readers who hit a wall. Each one is a recognized consumer right or documented escalation path.

1Related playbook: /claims/guides/auto-uninsured-motorist-claim-guide
2Request the denial or short-pay decision in writing citing specific policy language.
3Compare your file against the related Insurhi playbook before escalating.
4If the carrier misses your state's prompt-pay timeline, send a written demand referencing the statute.

Paper trail

Talking to the carrier and your state regulator

How you communicate matters. These notes help you keep a written paper trail and use language carriers and state DOIs recognize.

Confirm verbal commitments in a follow-up email with deadlines.
Log adjuster name, direct line, and supervisor contact on every call.
Use claim number and policy number in every email subject line.

Editorial disclosure

Insurhi content is informational only and is not legal, financial, or insurance advice.
Always read the full policy wording and confirm coverage, exclusions, and pricing with a licensed insurer or agent before purchase.
Rankings and product comparisons are independent. We do not accept payment for placement; affiliate relationships, when present, are clearly disclosed.
Found an error? Please email editorial@insurhi.com so we can review and correct within 48 hours.

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