On April 25, 2008, the Alaska Supreme Court held that a City of Valdez property tax, apportioned based on days docked in the City over days docked everywhere and imposed on large vessels, did not violate the Due Process, Commerce or Tonnage Clauses of the U.S. Constitution. City of Valdez v. Polar Tankers, S-12218/12223, Supreme Court of Alaska (April 25, 2008). In 2000, the City of Valdez (the "City") adopted a personal property tax (the "Vessel Tax") to compensate for its declining oil and gas property revenues. Revenues were declining as a result of a depreciation formula negotiated by the State of Alaska and the owners of the Trans Alaska Pipeline System (the "TAPS"), which included Conoco Phillips and Exxon Mobil, in the mid-1980s.