TITLE 26. INTERNAL REVENUE CODE § 6621. Determination of rate of interest., 26 USCS § 6621

Summary

(a) General rule.

(1) Overpayment rate. The overpayment rate established under this section shall be the sum of—

(A) the Federal short-term rate determined under subsection (b), plus

(B) 3 percentage points (2 percentage points in the case of a corporation).

To the extent that an overpayment of tax by a corporation for any taxable period (as defined in subsection (c)(3), applied by substituting “overpayment” for “underpayment”) exceeds $10,000, subparagraph (B) shall be applied by substituting “0.5 percentage point” for “2 percentage points”.

(2) Underpayment rate. The underpayment rate established under this section shall be the sum of—

(A) the Federal short-term rate determined under subsection (b), plus

(B) 3 percentage points.

(b) Federal short-term rate. For purposes of this section—

(1) General rule. The Secretary shall determine the Federal short-term rate for the first month in each calendar quarter.

(2) Period during which rate applies.

(A) In general. Except as provided in subparagraph (B), the ...