ETASSUM27110 | Schedule 2 share incentive plan (SIP): Notification & Enquiries: Information powers
From HM Revenue & Customs · Employee Tax Advantaged Share Scheme User Manual
Paragraph 93 provides the authority for an officer of HMRC to request information from companies with a Schedule 2 SIP:
which the officer reasonably requires for the performance of any functions of HMRC or an officer of HMRC under the SIP code, and
which the person to whom the notice is addressed can reasonably obtain.
In particular this may be to check anything in or accompanying a notice or return, or requested to determine the tax liability of any SIP participant or other person whose liability to tax the operation of the SIP is relevant to.