The single most important conversation you can have with your insurance agent is also the one most Missouri drivers never have. It is not about your rates, your deductible, or whether you should add roadside assistance. It is about how much uninsured and underinsured motorist coverage you carry — because in roughly half the serious injury cases we see, that coverage is the only meaningful source of recovery.

This article explains Missouri's uninsured motorist (UM) and underinsured motorist (UIM) coverage: what they are, what the law requires, when they pay, and why the right limits matter so much when an at-fault driver has no insurance or not enough.

The Missouri minimum is dangerously low

Missouri requires every registered vehicle to carry minimum liability coverage of $25,000 per person and $50,000 per accident for bodily injury, plus $25,000 for property damage. That is the 25/50/25 rule under RSMo §303.190. It is the lowest tier of coverage a Missouri driver can legally have.

Twenty-five thousand dollars is the cost of an MRI, a few weeks of physical therapy, and a single specialist consult. It is not enough to cover a fractured wrist that requires surgery. It is certainly not enough to cover a herniated disc, a hospitalization, or a permanent injury. Yet a large share of Missouri drivers carry exactly this much.

According to Insurance Research Council estimates, roughly 13% of Missouri drivers carry no insurance at all. Many more carry only the state minimum. When one of them hits you, your own UM or UIM coverage is what stands between you and the medical bills.

Uninsured motorist coverage (UM)

Missouri is one of the few states that requires UM coverage. Under RSMo §379.203, every auto policy issued in Missouri must include uninsured motorist bodily injury coverage of at least $25,000 per person and $50,000 per accident. You cannot legally buy a Missouri auto policy without it.

UM pays when you are injured by a driver who has no liability insurance, by a hit-and-run driver who flees the scene, or by a driver whose insurer becomes insolvent. To collect, you essentially step into the shoes of the at-fault driver and make a claim against your own carrier as if your carrier were that driver's insurer. Your carrier defends as if it were the defendant. Disputes about fault and damages are usually resolved by arbitration under the policy.

Underinsured motorist coverage (UIM)

UIM is different. UIM applies when the at-fault driver has some liability insurance, but not enough to cover your damages. If you have $100,000 in damages and the at-fault driver carried only $25,000, the $75,000 gap is what UIM is designed to fill.

Unlike UM, UIM is not mandatory in Missouri. You have to ask for it, and you have to pay for the higher limits. Most carriers will sell UIM up to the limit of your liability coverage. If you carry $250,000 in liability, you can usually buy $250,000 in UIM. The premium difference is often modest — a few extra dollars a month for tens of thousands of dollars of additional protection.

Stacking — the multiplier most drivers do not know about

Missouri allows "stacking" of UM coverage in many circumstances. Stacking means combining the UM limits of multiple vehicles or multiple policies to create a larger pool of available coverage.

A two-car household with $100,000 UM on each car may, depending on policy language, stack the coverage to a combined $200,000. A driver covered as a household member on a parent's policy may stack that policy with their own. The Missouri Supreme Court has addressed stacking repeatedly — see Ritchie v. Allied Property & Casualty Insurance Co., 307 S.W.3d 132 (Mo. banc 2009) — and has generally favored coverage when policy language is ambiguous.

Whether stacking is available depends on policy language and on whether the carrier validly excluded it. A close reading of the declarations page, the policy form, and any anti-stacking endorsement is required. We routinely find stacking opportunities clients did not know they had.

When UM and UIM actually kick in

The mechanics matter. A few rules to keep in mind:

  • Notice. Tell your carrier promptly after the accident. Most policies require prompt notice as a condition of coverage.
  • Settle the underlying claim first — but only with consent. Most UIM policies require you to give the carrier a chance to "substitute" its payment for the at-fault driver's settlement. The substitution preserves the carrier's right to subrogate against the at-fault driver. Settling without consent can void UIM coverage entirely.
  • Watch for offsets. Some UIM policies pay only the difference between their limit and what the at-fault driver paid. Others pay on top. The policy language controls.
  • Statute of limitations. A UM/UIM claim is a contract claim, not a tort claim. Missouri's contract statute of limitations is generally ten years (RSMo §516.110), longer than the five-year tort SOL — but waiting is still risky.

What to ask your insurance agent today

If you have not had this conversation in the last five years, it is worth ten minutes of your time:

  1. What is my current UM bodily injury limit?
  2. Do I have UIM, and if so, what is the limit?
  3. Can I stack across my household vehicles?
  4. What would it cost to raise both UM and UIM to $250,000 or $500,000?

The premium difference between a 25/50 policy and a 250/500 policy with matching UIM is typically a few dollars a month. The practical difference, on the day you need it, can be the difference between a $25,000 settlement and a $250,000 settlement on the same injury.

How this plays out in real cases

A Florissant client we represented was T-boned at a controlled intersection by a driver carrying state-minimum coverage. Damages — surgery, six months off work, permanent restriction — totaled around $180,000. The at-fault carrier paid its $25,000 limit on the first demand. The remaining $155,000 came almost entirely from our client's own UIM coverage, which she had wisely raised to $250,000 several years earlier on her agent's recommendation.

Without that UIM coverage, the case would have ended at $25,000. The medical bills alone would have consumed it. The client would have been left absorbing six months of lost wages and a lifetime restriction with no recovery.

Buy as much UM and UIM as you can comfortably afford. It is the cheapest insurance dollar-for-dollar most drivers can buy. For more on Missouri auto cases generally, see our pieces on comparative fault and on who pays medical bills after a Missouri accident, and our car accident practice page.

This article is general legal information for Missouri residents. It is not legal advice. Missouri law changes regularly — statutes are amended, case law evolves, and the application of any rule depends on the specific facts of each case. Do not act, or refrain from acting, based on this article without consulting a qualified Missouri attorney about your particular situation. Reading this article does not create an attorney-client relationship. For advice on your specific case, contact David Naumann & Associates at (314) 831-9350. The initial consultation is free. See the full Legal Disclaimer for complete terms.