Executive Summary: As promised, the Internal Revenue Service has prescribed special procedures that employers may use in order to retroactively correct FICA withholding and payment following the Supreme Court’s decision earlier this year in United States v. Windsor, and last month’s Revenue Ruling 2013-17 (the “Ruling”), under which same-sex couples are treated as married for all federal tax purposes if they were legally married, regardless of residence. For background, see our previous Legal Alert: IRS Answers Residence Question for Same Sex Spouses, at http://www.fordharrison.com/9568, and the article linked therein.