# The Taxes (Interest Rate) (Amendment) Regulations 2026

S.I. 2026/347 · made 24 March 2026

These Regulations amend the Taxes (Interest Rate) Regulations 1989/1297 (“1989 Regulations”). The 1989 regulations specify rates of interest for the purposes of the enactments specified in section 178(2) of the Finance Act 1989 (c. 26). The amendments made by these Regulations specify the applicable rates of interest for unpaid and overpaid amounts of multinational top-tax and domestic top-up tax.

Made under: Finance Act 1989 (Section 178)

PDFs: Printed copy https://openlegislation.uk/taxes-interest-rate-amendment-regulations-2026/pdf/uksi_20260347_en.pdf; UK Explanatory Memorandum https://openlegislation.uk/taxes-interest-rate-amendment-regulations-2026/pdf/uksiem_20260347_en_001.pdf

## Introductory text

DOMESTIC TOP-UP TAX
MULTINATIONAL TOP-UP TAX
Made 24th March 2026
Laid before the House of Commons 26th March 2026
Coming into force 17th April 2026
The Treasury make these Regulations in exercise of the powers conferred by section 178(1), (2)(x) and (y) and (3)(a) to (c), (e) and (f) of the Finance Act 1989.

## 1 Citation and commencement

These Regulations may be cited as the Taxes (Interest Rate) (Amendment) Regulations 2026 and come into force on 17th April 2026.

## 2 Amendment of the Taxes (Interest Rate) Regulations 1989

(1) The Taxes (Interest Rate) Regulations 1989 are amended as follows.
(2) After regulation 3ZE, insert—
“Applicable rate of interest on unpaid multinational top-up tax and domestic top-up tax
3ZF (1) For the purposes of paragraph 33 of Schedule 14 to the Finance (No. 2) Act 2023, with respect to unpaid multinational top-up tax and domestic top-up tax, the rate applicable under section 178 shall, subject to paragraph (2), be 7.75% per annum.
(2) Where on a reference date after 17th April 2026 the reference rate found on that date differs from the established rate, the rate applicable under section 178 for the purposes mentioned in paragraph (1) shall, on and after the next operative date, be the percentage per annum found by applying the formula specified in paragraph (3).
(3) The formula specified in this paragraph is—
R R + 4 , where RR is the reference rate referred to in paragraph (2).
Applicable rate of interest on overpaid multinational top-up tax and domestic top-up tax
3ZG (1) For the purposes of paragraph 33A of Schedule 14 to the Finance Act (No. 2) 2023, with respect to overpaid multinational top-up tax and domestic top-up tax, the rate applicable under section 178 shall, subject to paragraph (2), be 2.75% per annum.
(2) Where on a reference date after 17th April 2026 the reference rate found on that date differs from the established rate, the rate applicable under section 178 for the purposes mentioned in paragraph (1) shall, on and after the next operative date, be the higher of—
(a) 0.5% per annum, and
(b) the percentage per annum found by applying the formula specified in paragraph (3).
(3) The formula specified in this paragraph is—
R R - 1 , where RR is the reference rate referred to in paragraph (2).”.

## Signature

Taiwo Owatemi
Stephen Morgan
Two of the Lords Commissioners of His Majesty’s Treasury
24th March 2026

## Explanatory note

(This note is not part of the Regulations)
These Regulations amend the Taxes (Interest Rate) Regulations 1989/1297 (“1989 Regulations”). The 1989 regulations specify rates of interest for the purposes of the enactments specified in section 178(2) of the Finance Act 1989 (c. 26). The amendments made by these Regulations specify the applicable rates of interest for unpaid and overpaid amounts of multinational top-tax and domestic top-up tax.
Multinational top-up tax was introduced by Part 3 of the Finance (No. 2) Act 2023 (c. 30).
Domestic top-up tax was introduced by Part 4 of the Finance (No. 2) Act 2023 (c. 30).
Regulation 2 inserts new regulations 3ZF and 3ZG which specify the interest rate applicable under section 178 of the Finance Act 1989 (c. 26) in relation to unpaid and overpaid multinational top-up tax and domestic top-up tax.
A Tax Information and Impact Note covering this instrument was published on 15th March 2023 entitled ‘Multinational top-up tax and Domestic top-up tax: UK adoption of OECD Pillar 2’ alongside the Autumn Finance Bill 2023, and is available on the government website at https://www.gov.uk/government/collections/tax-information-and-impact-notes-tiins. It remains an accurate summary of the impacts that apply to this instrument.

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Source: https://www.legislation.gov.uk/uksi/2026/347 (the official version)
Page: https://openlegislation.uk/taxes-interest-rate-amendment-regulations-2026
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.