John W. Mann appeals pro se the dismissal of his complaint of fraud, replevin, and conversion against Salvatore Davide, Jeffrey Feiler, William Troy, and Joan Schwartz. The district court dismissed Mann’s complaint for lack of subject-matter jurisdiction. Fed.R.Civ.P. 12(b)(1). The district court ruled that the complaint failed either to state a claim arising under federal law, 28 U.S.C. § 1331, or to allege complete diversity of citizenship among the parties, id. § 1332(a), and Mann does not challenge that ruling. Mann complains that he was denied an opportunity to present his case, but he fails to explain how the district court had subject-matter jurisdiction over his case. As a result, we affirm the dismissal of Mann’s complaint.

AFFIRMED.