Glossary
Stacking, defined
Combining the uninsured or underinsured motorist limits from more than one vehicle, or more than one policy, so that a single injury claim can draw on the total. Where it is allowed, a household with two cars on the same policy can effectively double the limit available.
In practice
Whether it is allowed is a matter of state law and policy language, and it comes in two forms. Intra-policy combining adds the limits of vehicles on the same policy; inter-policy combining lets an injured person claim under their own policy and then under a relative's policy in the same household. Some states permit it, some ban it, and some let carriers charge for it and require a written rejection; in Arizona, the Department of Insurance and Financial Institutions can confirm the current rule. Where it is available, the additional premium is often modest compared with buying higher limits outright, but the mechanics are worth understanding before relying on it. An agent should be able to say which rule applies and whether the current policy has it turned on.
A worked example
Suppose a family insures two cars on one policy with $50,000 per person of underinsured motorist coverage on each. One family member is hit by a driver carrying a low limit and has a $120,000 injury claim. If limits can be combined, $100,000 is available from the family's own policy; if not, only $50,000. Hypothetical figures.
Applies to: Auto Insurance