ESMA officials and other authorised persons may conduct investigations of the persons referred to in Article 23b(1). They are empowered to examine records, data, procedures and other material in any medium; take or obtain certified copies or extracts; summon and obtain oral or written explanations from those persons, their representatives or staff and record the answers; interview consenting third parties; and request records of telephone and data traffic.

Investigations require written authorisation specifying subject matter and purpose and indicating periodic penalty payments under Article 36b and fines under Article 36a (in conjunction with point 8 of Section II of Annex III) for non‑cooperation or misleading answers. ESMA decisions must be notified to the person subject to investigation and to the competent national authority in good time; national officials may assist or attend. Where national judicial authorisation is required for telephone or data traffic, the national judicial authority reviews authenticity and proportionality of coercive measures but not the necessity of the investigation; lawfulness of ESMA's decision is for review only by the Court of Justice of the European Union under Regulation (EU) No 1095/2010.