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HMRC internal manual

National Insurance Manual

Class 1 NICs: reporting NICs in RTI: correction of errors under RTI: in year

Social Security (Contributions) Regulations, Schedule 4, paragraph 21E

If there’s an inaccuracy in the calculation and/or reporting of:

  • earnings for NICs purposes
  • primary or secondary NICs

during a tax year or, at the end of the tax year but before 20 April, they should correct the error as soon as possible, on their next Full Payment Submission (FPS), or an additional FPS.

Change in category letter

If the error involves a change of category letter, the employer should continue to report all categories used in a tax year, unless that category should never have been used at all (see fix problems with running payroll).