Also known as: diverse citizenship · diversity jurisdiction · 28 U.S.C. § 1332 · complete diversity
Written by attorneys · grounded in primary & secondary sources — see below
A basis for federal-court jurisdiction that exists when a case is between citizens of different states or between a citizen of a state and an alien and the matter in controversy exceeds seventy-five thousand dollars. Citizenship of an individual is determined by domicile. A corporation is a citizen of both its state of incorporation and the state of its principal place of business.
Dylan Duffy, a citizen of State A, sues Dawson Steel, a citizen of State B, in federal court for breach of contract seeking eighty thousand dollars. After filing, Dylan joins an additional claim against Dawson for related property damage worth twenty thousand dollars that shares the same operative facts. The court exercises supplemental jurisdiction over the smaller claim because complete diversity exists and the anchor claim meets the amount requirement.
Danielle Dixon, domiciled in State A, sues Dover Bank, incorporated and with its principal place of business in State B, for fraud. The suit is filed while Danielle remains a citizen of State A. Two weeks later Danielle moves permanently to State B. The federal court retains diversity jurisdiction because citizenship is measured at the time the action is commenced.
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Demetrius Douglas, a citizen of State A, sues Duffy Construction, a citizen of State B, in federal court for negligence arising from a construction accident. The court applies State A tort law to the dispute because the case rests solely on diversity jurisdiction and no federal statute or constitutional provision supplies a different rule of decision.
Deborah Dunn, a citizen of State A, sues Davenport Pharmaceuticals, a citizen of State B, in federal court for product liability. The defendant requests a jury trial on an issue that State B would assign to the judge. The federal court applies its own procedural rules to the jury-trial question while still respecting the underlying state substantive standard.
Delilah Duran, a citizen of State A, sues Dawson Steel, a citizen of State B, in federal court for breach of contract. State A law treats a particular contract defense as substantive and outcome-determinative. The federal court applies the State A rule because failure to do so would produce a different result than the same suit filed in State A court.
Dwight Dorsey, a citizen of State A, sues Dover Bank, a citizen of State B, in federal court for conversion of funds. The bank argues for a uniform federal rule on the effect of a mistaken payment. The court rejects the argument and applies State A law because the only basis for federal jurisdiction is diversity of citizenship.
Diversity must exist at the time the suit is instituted. It need not exist when the cause of action arose and is not defeated by subsequent changes in citizenship after filing.
Yes, provided at least one plaintiff's claim satisfies the amount requirement, complete diversity exists, and the additional claim shares a common nucleus of operative fact with the anchor claim.
A corporation is a citizen of both the state in which it is incorporated and the state in which it has its principal place of business.
Supporting sources
The federal court lacks diversity jurisdiction and must dismiss the action for lack of subject-matter jurisdiction even if the case has already proceeded to trial.
Supporting sources
…granted certiorari. First. Swift v. Tyson , 16 Pet. 1, 18, held that federal courts exercising jurisdiction on the ground of diversity of citizenship need not, in matters of general jurisprudence, apply the unwritten law of the State as declared by its highest court; that they are free to exercise an independent judgment as to what the…