1. When the Commission intends to carry out a market investigation with a view to the possible adoption of decisions pursuant to Articles 17, 18 and 19 it shall adopt a decision opening a market investigation.

2. Notwithstanding paragraph 1, the Commission may exercise its investigative powers under this Regulation before opening a market investigation pursuant to that paragraph.

3. The decision referred to in paragraph 1 shall specify:

(a) the date of opening of the market investigation;

(b) the description of the issue to which the market investigation relates to;

(c) the purpose of the market investigation.

4. The Commission may reopen a market investigation that it has closed where:

(a) there has been a material change in any of the facts on which a decision adopted pursuant to Article 17, 18 or 19 was based; or

(b) the decision adopted pursuant to Article 17, 18 or 19 was based on incomplete, incorrect or misleading information.

5. The Commission may ask one or more national competent authorities to assist it in its market investigation.