Buy your car policies together and you count as one insured, not two. Arizona's top court just handed carriers cleaner path to enforce anti-stacking clauses.
The Arizona Supreme Court held on July 6, 2026 that a claimant could not tap several of his family's policies for extra underinsured motorist money after a 2019 crash. For auto carriers, the ruling sharpens a costly question: when can you cap recovery to a single policy?
Stacking lets an injured person collect underinsured motorist (UIM) benefits from more than one policy for the same accident. Arizona allows it unless the insurer clearly forbids it in writing.
The claimant's family held several State Farm policies. His own, on a 2013 Hyundai Elantra, carried up to $250,000 in UIM coverage. Four others, held by his parents, each carried $250,000 per person on a 2001 Jeep Wrangler, a 2007 Mercedes S550, a 2016 Infiniti QX80, and a 2015 Kia Soul. The parents paid for those four with community funds.
On April 5, 2019, the claimant was a passenger in a crash, and his injuries outran the at-fault driver's coverage. State Farm paid the limits on his Hyundai policy and on one of his parents' four policies, then declined to stack the remaining three.
The insurer leaned on the anti-stacking clause in all five policies: "Only the one policy selected by the insured shall apply and no coverage will be provided by any of the other policies."
The claimant argued his parents were two insureds, not one, so the clause should not sweep in all four of their policies. The court disagreed. The "purchaser," it held, is the named insured who exercises the legal authority to obtain the coverage - and the source of the premium money is beside the point. When two named insureds buy policies together, they act as a single purchasing unit and count as "one insured" under A.R.S. § 20-259.01(H).
The court affirmed summary judgment for State Farm and vacated the part of the appeals court decision that had read the statute differently.
Here's why it lands for carriers. The court read the clause and the statute together and let the insurer cap recovery at two sources - the injured driver's own policy and one household policy. Clear anti-stacking language, drafted around named insureds rather than premium-payers, holds up.
