The U.S. IRS has published Internal Revenue Bulletin No. 2026-6 of 2 February 2026. This includes, among other things, Announcement 2026-3, which contains the text of the Competent Authority Arrangement entered into by the competent authorities of the U.S. and Spain, with respect to the implementation of the arbitration process provided for in paragraphs 5 and 6 of Article 26 (Mutual Agreement Procedure) of the 1990 U.S.-Spain tax treaty. Broadly, the arrangement covers the rules, timeline…