Rule 301 Federal Rules of Evidence
Rule 301 of the Federal Rules of Evidence is about Presumptions in Civil Cases Generally. It is under Article III (Presumptions in Civil Cases) of the Rules.
In a civil case, unless a federal statute or these rules provide otherwise, the party against whom a presumption is directed has the burden of producing evidence to rebut the presumption. But this rule does not shift the burden of persuasion, which remains on the party who had it originally.