## Uninsured / underinsured motorist (UM/UIM) coverage in Massachusetts If you're hit by a driver who has no insurance — or has insurance with limits too low to cover your damages — your own UM/UIM policy steps in. Without it, you may have no realistic source of recovery. ### Massachusetts UM/UIM rules - **Required?** Mandatory - **State minimum:** $20K/$40K ## When UM/UIM kicks in **Uninsured (UM):** - The at-fault driver had no insurance - The at-fault driver fled the scene (hit-and-run) and can't be identified — varies by state, often requires physical contact - The at-fault driver's insurer denied the claim or went insolvent **Underinsured (UIM):** - The at-fault driver's policy limits are LESS than your damages - You collect the at-fault driver's full limits, then your UIM tops up the difference - Different states use different formulas to calculate the offset ## Stacking **Stacking** = combining UM/UIM limits across multiple policies or vehicles. - **Intra-policy stacking** — combining limits of multiple vehicles on a single policy - **Inter-policy stacking** — combining UM coverage from different policies (yours + relative living in your home) Some states allow stacking by default; some require an opt-in; some prohibit it. Stacking can multiply your coverage 2x-5x or more. ## Why mandatory UM doesn't always mean adequate UM Many states require minimum UM coverage at the state's minimum liability levels — typically $25K/$50K. That's NOT enough for a serious injury. A two-week ICU stay alone can exceed $250K. Buy UM at substantially higher levels — $100K/$300K or $250K/$500K is common for adequate coverage. ## How UM/UIM claims work 1. **Investigate the at-fault driver's coverage** — get the declarations page 2. **Pursue the at-fault driver's policy first** — exhaust their limits 3. **Notify your UM/UIM carrier promptly** — most policies require notice within a defined window 4. **Provide proof of damages** — medical records, bills, lost wages 5. **Negotiate** — your insurer becomes effectively the defendant in your own claim 6. **Arbitration or lawsuit** — most UM/UIM policies require arbitration before litigation ## Hit-and-run rules Hit-and-run accidents typically require: - **Physical contact** between vehicles (in many states) — "phantom vehicle" claims (where another driver caused the crash without contact) face higher hurdles - **Police report filed promptly** — typically within 24-72 hours - **Witness corroboration** for some states Without these, the UM claim may be denied. ## Bad-faith claims Insurance companies are required to handle UM claims in good faith. When they delay, lowball, or deny without reasonable basis, you may have a separate **bad-faith** claim that exposes the insurer to: - Damages above policy limits - Punitive damages - Attorney's fees and costs - Statutory penalties in some states ## Setoff for collateral sources Most UM/UIM policies offset for amounts received from: - Workers' compensation (if injury was work-related) - The at-fault driver's liability policy - Med-pay (in some states) - PIP / no-fault benefits Some states have collateral-source rules that LIMIT the insurer's offset rights. ## What you should do Most people don't realize they have UM/UIM coverage until after an accident. If you've been hit by an uninsured or underinsured driver in Massachusetts, talk to a personal-injury attorney immediately. Most attorneys offer free consultations and work on contingency. Don't sign a release with the at-fault driver's insurance until your UM/UIM carrier has approved — premature release can void your UM claim. --- *This guide is general information about Massachusetts law as of early 2026 and is not legal advice. UM/UIM rules vary widely between states (stacking, offsets, hit-and-run thresholds) and policy terms add their own nuances. Talk to a licensed Massachusetts attorney about your specific case.*