In United States v. Stein, 881 F.3d 853 (11th Cir. 2018) the appeals court held that an affidavit satisfying Rule 56 of the Federal Rules of Civil Procedure may create an issue of material fact and preclude summary judgment even if it is self-serving and uncorroborated.
The case concerned IRS assessments, which amount to an IRS determination that a taxpayer owes the federal government a certain amount of unpaid taxes, and is entitled to a legal presumption of correctness. In 2015, the government sued Estelle Stein for outstanding tax assessments, late penalties, and interest owed. In response to the government’s later summary judgment motion, Stein submitted an affidavit of her own stating that, to the best of her recollection, she had paid the taxes and penalties owed for the years in question.