The Assessor establishes the value of the unsecured property on January 1. This date is often referred to as the Tax Lien date. Ownership on the lien date, determines the obligation to pay taxes: Disposal, removal, or sale of the object of the assessment after the lien date will not affect the tax bill nor relieve the assessee of liability. No proration is made by the Tax Collector on unsecured taxes. Any proration is strictly a private matter between buyer and seller.