The Treasury Department finalized regulations defining who is considered married for federal tax purposes to reflect the holdings in the Supreme Court decisions in Windsor v. United States and Obergefell v. Hodges, which upheld same-sex marriages. Under the regulations, the terms “spouse,” “husband,” and “wife” denote an individual who is legally married to another individual. The terms are gender neutral; they include same-sex, as well as opposite-sex, marriages.

A marriage in the United States is recognized as a marriage for federal tax purposes if the marriage is recognized in the state, possession or territory in which it was entered into, regardless of where the individuals are domiciled. A foreign marriage is recognized if the relationship would be recognized as a marriage in any state, possession or territory of the United States.

On the other hand, individuals who have entered into alternative arrangements not denominated as marriage under the laws of the state, possession or territory of the United States where the relationship was entered into (e.g., registered domestic partnerships and civil unions) are not considered married for federal income tax purposes. The Treasury rejected the requests by some commentators to treat such individuals as married where the rights granted by such alternative status are substantially similar to the rights of married individuals, on the basis that doing so would be too burdensome on the government and the taxpayers, and is contrary to the expectations of the individuals who chose the alternative to entering into a marriage. Moreover, the fact that such couples may face uncertainty in their tax treatment upon the dissolution of such an alternative arrangement is not a reason to change the definition of a marriage. The federal government will continue to look to state laws to define marriage.