Iowa Code § 321.70: Dealer vehicles.

A dealer licensed under chapter 322 shall not be required to register any vehicle owned by the dealer which is being held for sale or trade, provided the annual registration fee was not delinquent at the time the vehicle was acquired by the dealer. When a dealer ceases to hold any vehicle for sale or trade or the vehicle otherwise becomes subject to registration under this chapter the annual registration fee and delinquent annual registration fee, if any, shall be due for the registration year.