This document contains final regulations relating to the treatment of open account debt between S corporations and their shareholders. These final regulations provide rules regarding the definition of open account debt and the adjustments in basis of any indebtedness of an S corporation to a shareholder under section 1367(b)(2) of the Internal Revenue Code (Code) for shareholder advances and repayments on advances of open account debt. The regulations affect shareholders of S corporations and are necessary to provide guidance needed to comply with the applicable tax law.