Cal. Revenue and Taxation Code § 6277

There shall be a presumption that a transfer of a vehicle to a lessee by a lessor, as defined in Section 372 of the Vehicle Code, was a sale for resale if the lessee transfers title and registration to a third party within 10 days from the date the lessee acquired title from the lessor at the expiration or termination of a lease. The presumption may be rebutted by evidence that the sale was not for resale prior to use. It is the intent of the Legislature in enacting this section to recognize the delay in processing documents when a lessee wishes to transfer title of a leased vehicle to a third party at the expiration or termination of a lease rather than acquiring a vehicle for his or her own use. This section does not provide an exemption for any use by a lessee after the expiration or termination of a lease.