An insider list is a record maintained by an issuer or other entity identifying all persons who have access to inside information about the issuer or its financial instruments, together with the time and circumstances in which that access arose and ceased. In practice, it is a core compliance tool in capital markets and listed company governance, used to manage market abuse risk and demonstrate regulatory compliance.For issuers with securities admitted to trading on UK or EU regulated markets or prescribed venues, insider lists are required under the UK Market Abuse Regulation (UK MAR) and the EU Market Abuse Regulation (EU MAR), as onshored or implemented in the UK, Ireland and, broadly consistently, across England & Wales, Scotland and Northern Ireland. Prescribed content includes names, roles, contact details, reasons for inclusion, and timestamps.Insider lists are used by compliance and company secretarial teams to control disclosure of inside information, supervise staff personal dealing, and respond to inquiries from regulators such as the FCA and the Central Bank of Ireland. Failure to keep accurate, up‑to‑date insider lists can be treated as a breach of market abuse and listing obligations, with significant regulatory, civil and reputational consequences.