Does Hawaii Allow UM/UIM Stacking? What Section 431:10C-301 Says

By the FigureMyTax Editorial Team · How we calculate

Hawaii's statute prohibits stacking or aggregating UM and UIM coverage except through an option that every insurer must offer with each policy.

The prohibition

Section 431:10C-301(c) says: the stacking or aggregating of uninsured motorist coverage or underinsured motorist coverage is prohibited, except as provided in subsection (d).

The required offer

Subsection (d) says an insurer shall offer the insured the opportunity to purchase UM and UIM coverage by offering (1) the option to stack, and (2) the option to select UM and UIM coverage up to but not greater than the bodily injury liability limits in the policy. For policies that already existed, the offer was due at the first renewal after January 1, 1993. Once an insured has been given the opportunity to purchase or reject in writing, no further offer is required with a renewal or replacement policy.

If you rejected UM/UIM

If UM or UIM coverage is rejected, the stacking offers are not required, no further offers are needed on renewal, and the written rejection is presumptive evidence of your decision to reject the options (subsection (e)). A material change to a policy after a valid rejection can require a new offer, according to an annotation to the statute (93 Haw. 210).

What it leaves open

The statute does not define how stacked limits are measured against the at-fault driver's payment, or what "other insurance" clauses do across separate policies. We did not read the cases beyond the annotations on the official site, so ask an attorney before assuming your policies add up or do not.

How to use this

Compare the single-limit and stacked results in the Hawaii UM/UIM stacking calculator, start with the plain-English stacked versus unstacked explainer, and read how UM and UIM differ.

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