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HMRC internal manual

National Insurance Manual

Class 1 NICs: interest: repayment interest

Section 102 Finance Act (FA) 2009 Repayment interest on sums to be paid by HMRC

Section 102(3) FA 2009 applies interest at the repayment interest (RPI) rate from the RPI start date until the date on which the payment or repayment is made.

Section 102(4) FA 2009 applies Schedule 54 to define the RPI start date.

Schedule 54(2) to (4) FA 2009 provides the general rule for determining the RPI start date for an amount which has been paid to HMRC. This is the later date between:

  1. the date on which the amount was paid to HMRC; and
  2. the date on which the payment became due and payable.


Tax year 2018 to 2019.

Secondary Class 1 NICs overpaid for Month 1, paid to HMRC on 6 May 2018.

Month 1 NICs became due and payable on 19 May 2018.

Repayment made by HMRC on 30 July 2018 following employer refund request.

RPI paid from 19 May to 30 July 2018 (the due date of 19 May being later than the date the Secondary Class 1 NICs was paid).