NIM01003 - Class 1 Structural Overview: Earnings periods
Regulation 2 of the Social Security (Contribution) Regulations 2001 (SI 2001 No 1004)
So that the contributions liability can be properly determined in the light of the various pay arrangements in existence, it is necessary to assign to each employee an earnings period (EP) in relation to each employment, if they have more than one. The rules for determining this period are set out in NIM08000 onwards.