§ 301.6621-1 Interest rate.

(a) In general. The interest rate established under section 6621 shall be— (1) On amounts outstanding before July 1, 1975, 6 percent per annum (or 4 percent in the case of certain extensions of time for payment of taxes as provided in sections 6601 (b) and (j) prior to amendment by section 7(b) of the Act of Jan. 3, 1975 (Pub. L. 93-625, 88 Stat. 2115), and certain overpayments of the unrelated business income tax as provided in section 514(b)(3)(D), prior to its amendment by such Act). (2) On amounts outstanding— (3) On amounts outstanding after December 31, 1982, the adjusted rate established by the Commissioner under section 6621(b). This adjusted rate shall be published by the Commissioner in a Revenue Ruling. See § 301.6622-1 for application of daily compounding in determining interest accruing after December 31, 1982. Because interest accruing after December 31, 1982, accrues at the prescribed rate per annum compounded daily, the effective annual percentage rate of interest will exceed the prescribed rate of interest. (b) [Reserved] (c) Applicability of interest rate—(1) Computation. Interest and additions to tax on any amount outstanding on a specific day shall be computed at the annual rate applicable on such day. (2) Additions to tax. Additions to tax under any section of the Code that refers to the annual rate established under this section, including sections 644(a)(2)(B), 4497(c)(2), 6654(a), and 6655 (a) and (g), shall be computed at the same rate per annum as the interest rate set forth under paragraph (a) of this section. (3) Interest. Interest provided for under any section of the Code that refers to the annual rate established under this section, including sections 47(d)(3)(G), 167(q), 6332(c)(1), 6343(c), 6601(a), 6602, 6611(a), 7426(g), and section 1961(c)(1) or 2411 of title 28 of the United States Code, shall be computed at the rate per annum set forth under paragraph (a) of this section. (d) Examples. The provisions of this section may be illustrated by the following examples. Example 6 illustrates the computation of interest for interest accuring after December 31, 1982.