alcoa and its subsidiaries file income tax returns in the u.s . federal jurisdiction and various states and foreign jurisdictions . with a few minor exceptions , alcoa is no longer subject to income tax examinations by tax authorities for years prior to 2006 . all u.s . tax years prior to 2015 have been audited by the internal revenue service . various state and foreign jurisdiction tax authorities are in the process of examining alcoa 2019s income tax returns for various tax years through 2014