Definition of a Taxpayer (US Internal Revenue Service Regulation) (IRS) (2018 Edition) The Law Library presents the complete text of the Definition of a Taxpayer (US Internal Revenue Service Regulation) (IRS) (2018 Edition). Updated as of May 29, 2018 This document contains final Income Tax Regulations which provide guidance relating to the determination of who is considered to pay a foreign income tax for purposes of the foreign tax credit. These regulations provide rules for identifying the person with legal liability to pay the foreign income tax in certain circumstances. These regulations affect taxpayers claiming foreign tax credits. This book contains: - The complete text of the Definition of a Taxpayer (US Internal Revenue Service Regulation) (IRS) (2018 Edition) - A table of contents with the page number of each section