Iowa Code § 322A.23: Customer lists.

A condition, stipulation, or provision in a franchise which requires the franchisee to provide its customer lists or service files to the franchiser is void. This section shall not apply to notification by the franchisee to the franchiser of the delivery of a new motor vehicle to a customer, including information necessary to complete the sale of the vehicle, or to the submission to the franchiser of a claim for warranty parts, recalls, repairs, or services supplied or performed by the franchisee.