Does California Allow UM/UIM Stacking? What Section 11580.2 Says

By the FigureMyTax Editorial Team · How we calculate

No. Insurance Code 11580.2(q) bars stacking in plain terms, and subdivision (d) lets a policy pro-rate damages among multiple UM coverages by their limits instead.

The statutory text

Section 11580.2(q) says that regardless of the number of vehicles involved, whether insured or not, persons covered, claims made, premiums paid or the number of premiums shown on the policy, in no event shall the limit of liability for two or more motor vehicles or two or more policies be added together, combined or stacked to determine the limit of insurance coverage available to injured persons.

How it fits with subdivision (d)

Subdivision (d) says the policy or endorsement may provide that, if the insured has insurance available under more than one UM coverage provision, any damages shall not be deemed to exceed the higher of the applicable limits, and the damages shall be prorated between the applicable coverages as the limits of each bear to the total of the limits. So $100,000 and $50,000 policies do not yield $150,000; they yield at most $100,000, split two-thirds and one-third.

Other-vehicle rules

Subdivision (c)(2) says the coverage does not apply to bodily injury of the insured while in or on a motor vehicle other than the described one if its owner has similar insurance, and (c)(6) excludes injury while occupying a vehicle owned by an insured or leased to an insured for six months or more unless it is an insured motor vehicle. Which policy responds can therefore depend on what you were driving.

Underinsured claims are different

Subdivision (p) says it prevails over (a) through (o) if they conflict, but (q) is written without limiting it to uninsured coverage and nothing we read exempts underinsured coverage, so UIM limits are not stacked either. Under (p)(4), UIM pays no more than your UIM limits less what you received from the liable parties. Read how the limits-to-limits test works.

What to do with this

Use the California UM/UIM stacking calculator to see the difference between what stacking would have given and what California pays, and start with the plain-English comparison if the terms are new.

This is general information, not legal advice, and the state comparisons above are illustrative, not an exhaustive survey. Confirm how California's rules apply to your specific case with a licensed California attorney.