Interim final rule
A rule that takes effect immediately, with public comment collected after the fact rather than before it.
An interim final rule inverts the usual sequence. Instead of proposing, waiting, and then binding, the agency binds first and invites comment afterwards. The requirement is enforceable from its effective date, and the comment period runs against a rule that is already operating.
The Administrative Procedure Act permits this only where the agency finds good cause that ordinary notice and comment would be impracticable, unnecessary, or contrary to the public interest. That finding must be stated in the rule itself, which makes it checkable, and it is frequently the most newsworthy sentence in the document. A thin good-cause claim is the most common ground on which an interim final rule is later challenged.
For a reader the practical significance is timing. An interim final rule imposes an obligation now, so the question is not what an agency might eventually require but what is required today. A proposal can be watched; an interim final rule has to be complied with while the argument about it continues.
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