Interest rates: underpayments and overpayments. The rates for interest determined under Section 6621 of the code for the calendar quarter beginning October 1, 2023, will be 8 percent for overpayments (7 percent in the case of a corporation), 8 percent for underpayments, and 10 percent for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 5.5 percent.

26 CFR 301.6621-1: Interest rate.

This notice provides guidance with respect to section 603 of the SECURE 2.0 Act of 2022 and announces a 2-year administrative transition period with respect to the requirement under section 603 that catch-up contributions made on behalf of certain eligible participants be designated as Roth contributions. The notice also describes certain further guidance that the Treasury Department and the IRS anticipate issuing with respect to section 603 and requests comments.

Revocation of IRC 501(c) (3) Organizations for failure to meet the code section requirements Contributions made to the Organizations by individual donors are no longer deductible under IRC 170 (b)(1)(A)

Revocation of IRC 501(c) (3) Organizations for failure to meet the code section requirements Contributions made to the Organizations by individual donors are no longer deductible under IRC 170 (b)(1)(A).

This document contains corrections to Rev. Proc. 2023-27, as published on Monday, August 28, 2023 (I.R.B. 2023-35, 655) In particular, this announcement corrects four administrative items.

This revenue procedure provides the applicable percentage table in § 36B(b)(3)(A) of the Internal Revenue Code for taxable years beginning in calendar year 2024. This table is used to calculate an individual’s premium tax credit under § 36B. This revenue procedure also provides the indexing adjustment for the required contribution percentage in § 36B(c)(2)(C)(i)(II) for plan years beginning in calendar year 2024. This percentage is used to determine whether an individual is eligible for affordable employer-sponsored minimum essential coverage under § 36B.

26 CFR 601.105: Examination of returns and claims for refund, credit, or abatement; determination of correct tax liability.

(Also Part 1, §§ 36B, 1.36B-2, 1.36B-3.)

Federal rates; adjusted federal rates; adjusted federal long-term rate, and the long-term tax exempt rate. For purposes of sections 382, 1274, 1288, 7872 and other sections of the Code, tables set forth the rates for September 2023.