CBP quarterly notice: Q4 2026 IRS interest rates on customs-duty underpayments/refunds (procedural; no tariff-rate change)
In its quarterly notice (91 FR 60141), CBP advises, per 19 U.S.C. 1505 and T.D. 85-93, that for the calendar quarter beginning October 1, 2026 (through December 31, 2026), interest on underpayments of customs duties is 7% for both corporations and non-corporations, and overpayment interest is 7% for non-corporations and 6% for corporations — per IRS Revenue Ruling 2026-15 (4% federal short-term rate plus 3/2 percentage points). Routine quarterly interest notice; no tariff rate is changed. Note: the FR SUMMARY says the rates remain the same as the prior quarter, while the supplementary text says they increase — the document is internally inconsistent; this entry records the rates as stated. Prior-quarter values are not given; see the FR document.
Scope
No HTS impact (applies to interest on all customs underpayment/overpayment accounts)
Old → new values
| Item | Old value | New value |
|---|---|---|
| Underpayment interest rate, Q4 2026 | Prior-quarter rate not stated in the notice | 7% (corporate and non-corporate) |
| Overpayment interest rate, non-corporate | Prior-quarter rate not stated in the notice | 7% |
| Overpayment interest rate, corporate | Prior-quarter rate not stated in the notice | 6% |