Promoters and in some cases users of certain National insurance contributions (NICs) saving arrangements are obliged to disclose details of those arrangements to HMRC from 1 May 2007. This note sets out the types of arrangements that are caught by the NICs disclosure rules, who must disclose and when the disclosure must be made. The note also explains the consequences of HMRC issuing scheme reference numbers in respect of notified schemes and HMRC's new power issue such numbers for schemes that have not been notified, but which HMRC suspects should have been.