Tulsa Port Warehouse Company (Tulsa) (plaintiff) entered into four agreements with Chuck Naiman Buick Company (Chuck Naiman) for the use of vehicles for either 24 or 36 months. Chuck Naiman assigned its interest in the agreements to General Motors Acceptance Corporation (GMAC). Under the agreements, referred to as open-end leases, Tulsa made monthly payments for the use of the vehicles equal to the predetermined depreciation of the vehicles, plus interest. Pursuant to the agreements, Tulsa was required to obtain insurance on the vehicles in favor of GMAC, pay all fees and maintenance costs associated with the vehicles, and indemnify GMAC against all loss. At the end of the agreement, the vehicles were sold to third parties. If the vehicles sold for more than the depreciated value previously agreed upon, Tulsa was entitled to the surplus. If the vehicles sold for less than the depreciated value, Tulsa was required to pay GMAC the deficit. GMAC did not file a financing statement. Tulsa filed for bankruptcy. The bankruptcy trustee asserted a superior interest in the vehicles, because the trustee argued that the agreements created security interests, which GMAC had failed to perfect. GMAC argued that the agreements were leases. The bankruptcy court ruled in favor of the bankruptcy trustee, and GMAC appealed to the district court. The district court affirmed that decision, and GMAC appealed to the United States Court of Appeals for the Tenth Circuit.