CFR›Title 26›Chapter I›Part 1›Subject Group Changes in Rates During a Taxable Year›26 CFR 1.25F-5T Citation26 CFR 1.25F-5TCorpusDaily eCFRDisplayed edition2026-10-19Last updated2026-10-19 § 1.25F-5T xxxLink to an amendment published at 91 FR 62668, Oct. 2, 2026. Previous 1.25F-4T § 1.25F-4T xxx Next 1.28-0 § 1.28-0 Credit for clinical testing expenses for certain drugs for rare diseases or conditions; table of contents.