ESMA may investigate persons referred to in Article 38b(1). Authorised officials may examine records and procedures on any medium, take certified copies or extracts, summon and obtain oral or written explanations from those persons, interview consenting third parties and request records of telephone and data traffic. Officials must produce written authorisation specifying the subject matter and purpose of the investigation and must indicate applicable periodic penalty payments under Article 38i and fines under Article 38h for non‑compliance, incomplete, incorrect or misleading answers.

Persons referred to in Article 38b(1) are required to submit to investigations based on an ESMA decision that specifies subject, purpose, periodic penalty payments, available legal remedies under Regulation (EU) No 1095/2010 and the right to have the decision reviewed by the Court of Justice. ESMA shall inform the competent national authority in good time and may request assistance or attendance. Where judicial authorisation is required for telephone or data traffic records, ESMA shall apply; the national judicial authority shall verify the ESMA decision's authenticity and the proportionality of measures, may seek detailed explanations, shall not review the necessity of the investigation or demand ESMA’s file, and lawfulness is subject only to review by the Court of Justice under Regulation (EU) No 1095/2010.