(1) If the Bundeskartellamt institutes proceedings or conducts investigations, it shall simultaneously inform the supreme Land authority in whose district the undertakings concerned have their registered seat. If a supreme Land authority institutes proceedings or conducts investigations, it shall also inform the Bundeskartellamt.
(2) The supreme Land authority shall refer a matter to the Bundeskartellamt if the Bundeskartellamt is competent pursuant to Section 48(2) sentence 1 or Section 50(1). The Bundeskartellamt shall refer a matter to the supreme Land authority if the supreme Land authority is competent pursuant to Section 48(2) sentence 2.
(3) Upon application by the Bundeskartellamt, the supreme Land authority may refer to the Bundeskartellamt a matter falling under the competence of the supreme Land authority pursuant to Section 48(2) sentence 2, provided that this is expedient in view of the circumstances of the matter. Upon referral, the Bundeskartellamt shall become the competent competition authority.
(4) Upon application by the supreme Land authority, the Bundeskartellamt may refer to the supreme Land authority a matter falling under the Bundeskartellamt's competence pursuant to Section 48(2) sentence 1, provided this is expedient in view of the circumstances of the matter. Upon referral, the supreme Land authority shall become the competent competition authority. Prior to the referral, the Bundeskartellamt shall inform the other supreme Land authorities concerned. The referral shall not take place if a supreme Land authority concerned objects to this referral within a time limit to be set by the Bundeskartellamt.