Cost allocation in § 91a ZPO mootness proceedings: allocation based on probable merits outcome of unadjudicated revision

The Bundesgerichtshof (BGH) ordered the plaintiff to bear the full costs of the litigation following the parties' joint declaration that the matter was resolved. This cost allocation decision, rendered by the 11th Civil Senate, was based on an assessment that the plaintiff's revision appeal would have been unsuccessful had it proceeded to a substantive judgment, thereby establishing that the respondent prevailed on the merits of the underlying dispute. The case involved a civil procedure where the parties declared the matter moot (*erledigt*), prompting the court to apply the equitable discretion provided in German civil procedure law to determine costs. The decisive legal basis for the ruling was § 91a Abs. 1 of the Code of Civil Procedure (ZPO), which mandates cost allocation based on the probable outcome of the proceedings and the circumstances of the case, with the specific substantive issues being identified by reference to the Senate's earlier judgment in a related proceeding.