In Tax Notes, Mindy Herzfeld writes about two recent decisions from the Tax Court and the Court of Federal Claims in which the respective court each ruled against the government on the basis that Treasury exceeded its authority when it promulgated regulations implementing the 2017 tax overhaul informally known as the Tax Cuts and Jobs Act. From the piece:

The Tax Court and the Court of Federal Claims, in two decisions handed down in July — Siemens Medical Solutions USA Inc. v. Commissioner and Keysight Technologies Inc. v. United States— built on the foundations of a 2024 Tax Court decision, Varian Medical Systems Inc. v. Commissioner, to take down Treasury’s rulemaking authority another few notches. Both recent cases concern broadly expansive regulations issued in the aftermath of the Tax Cuts and Jobs Act. In the two decisions, the Tax Court and claims court rap Treasury on the knuckles for its overbroad interpretation of its authority to promulgate regulations that are clearly inconsistent with the plain language of the statutes. The cases may have wide repercussions for administrative lawmaking and taxpayer behavior.