Diversity of Citizenship: Complete Diversity, Amount, and Removal

Diversity of citizenship is the rule that lets a federal court hear a civil lawsuit that would otherwise belong in state court, so long as the opposing parties are citizens of different states (or one is a foreign citizen) and more than $75,000 is in dispute. The authority comes from Article III of the Constitution, which extends federal judicial power to “Controversies . . . between Citizens of different States,”¹ and Congress spelled out the specifics in 28 U.S.C. 1332.² Two conditions have to be met together: the right kind of citizenship mismatch between the parties, and enough money at stake.

How Citizenship Is Determined

Citizenship for this purpose is not where you currently live or pay taxes. For an individual, it turns on domicile: the one state you treat as your true, permanent home and where you intend to stay indefinitely.³ You can own a vacation home in Florida and spend every winter there, but if your permanent home is in Ohio and you plan to return, Ohio is your domicile. A person can only have one domicile at a time. Changing it requires both physically relocating and genuinely intending to stay in the new state.

Corporations work differently. A corporation is a citizen of every state where it is incorporated and the state where it has its principal place of business.² That principal place is the company’s “nerve center,” which the Supreme Court in Hertz Corp. v. Friend defined as the location where top officers direct and coordinate its activities.³ A company incorporated in Delaware and headquartered in New York is a citizen of both states.

Unincorporated entities like partnerships and limited liability companies are harder. Their citizenship depends on the citizenship of every single member or partner. An LLC with 50 members spread across 30 states is a citizen of all 30, which can make diversity much harder to establish than it would be for a corporation.

Foreign parties fit into the framework too. A lawsuit between a U.S. citizen and a citizen of a foreign country can qualify. But a lawful permanent resident who is domiciled in the same state as the opposing party is treated as a citizen of that state, which destroys diversity.²

The Complete Diversity Rule

Federal diversity jurisdiction requires what lawyers call complete diversity. No plaintiff can share citizenship with any defendant. If you sue two companies and one of them is incorporated in your home state, the entire case loses its diversity footing, even though the other defendant is from a different state. One overlap is enough to defeat jurisdiction.

Timing matters too. Courts measure citizenship at the moment the lawsuit is filed. If you and the defendant are citizens of different states on the day the complaint is filed, later changes do not destroy jurisdiction. And if diversity did not exist on the filing date, relocating afterward will not create it.

The Class Action Exception

Congress carved out a big exception for class actions through the Class Action Fairness Act. A qualifying class action only needs “minimal diversity,” meaning at least one class member is a citizen of a different state from at least one defendant. The aggregate amount in controversy also has to exceed $5,000,000 rather than the ordinary $75,000 threshold.² Individual class members’ claims get added together to reach that figure, which is not how the amount works in ordinary diversity cases.

The $75,000 Amount in Controversy

Diverse citizenship alone is not enough. The amount in controversy must exceed $75,000, not counting interest and court costs.² The figure the plaintiff pleads in the complaint generally controls, as long as it is asserted in good faith. A court will dismiss for failing to meet the threshold only if it is a “legal certainty” that the plaintiff cannot recover more than $75,000. Close calls go the plaintiff’s way.

A single plaintiff with multiple claims against a single defendant can add those claims together, even unrelated ones. A $50,000 contract dispute and a $30,000 property damage claim against the same defendant total $80,000 and satisfy the requirement. Multiple plaintiffs generally cannot pool their separate claims to cross the line. If one plaintiff in a multi-plaintiff case meets the $75,000 mark, though, the court may exercise supplemental jurisdiction over the smaller claims of the others under 28 U.S.C. 1367.⁴

Removing a State Case to Federal Court

One of the most practical uses of diversity jurisdiction is removal. If a plaintiff files suit in state court and the case satisfies the diversity requirements, the defendant can move it to the federal district court covering that location by filing a notice of removal.⁵⁶

The Forum Defendant Rule

There is a significant catch. A diversity case cannot be removed if any properly joined and served defendant is a citizen of the state where the suit was filed.⁵ The idea is that a defendant sued at home does not face the hometown-bias problem diversity jurisdiction was meant to address. Plaintiffs’ lawyers use this strategically by suing in a state where at least one defendant resides.

The One-Year Deadline

Diversity-based removal is also subject to a hard deadline. A defendant cannot remove a case more than one year after it was originally filed, unless the court finds the plaintiff acted in bad faith to prevent removal.⁶ Miss the window and the case stays in state court regardless of whether diversity exists.

Which Law Applies Once You’re in Federal Court

Moving a case to federal court does not mean federal law governs the dispute. Under the Erie doctrine, established in Erie Railroad Co. v. Tompkins (1938), a federal court hearing a diversity case applies the substantive law of the state whose law governs the claim, along with federal procedural law (the Federal Rules of Civil Procedure and Federal Rules of Evidence). The court does not craft its own legal standards just because the case landed in a federal courtroom.

A contract dispute between a Texas plaintiff and a California defendant, heard in federal court, is still decided under state contract law. The federal court is essentially a substitute state court for the governing rules while using its own procedures for how the trial runs. Whether a rule counts as substantive or procedural can be contested, but the guiding principle is that the outcome should be substantially the same as if the case had stayed in state court.

Cases Federal Courts Will Not Hear Anyway

Even when both requirements are satisfied, federal courts refuse certain categories that have traditionally belonged to state courts.

Domestic relations. Federal courts will not issue divorce decrees, set alimony, or make child custody orders. The Supreme Court confirmed this limit in Ankenbrandt v. Richards, holding that the domestic relations exception applies specifically to those three types of relief. A tort claim between ex-spouses can still qualify for diversity jurisdiction because it does not ask the court to issue one of those family-law decrees.⁷
Probate. Federal courts will not admit wills to probate or oversee estate administration. A dispute over assets that happens to involve an estate may still be heard in federal court, but core probate functions stay with the state courts.

What Happens If Jurisdiction Is Missing

If a federal court discovers at any point before final judgment that it lacks subject matter jurisdiction, the case has to be sent back to state court.⁸ This can happen because two opposing parties turn out to share citizenship, the amount in controversy was inflated, or a procedural defect in removal surfaces later. Challenges based on a complete lack of jurisdiction can be raised at any time, and diversity jurisdiction, like all federal jurisdiction, cannot be created by the parties’ consent or silence.

1
Constitution Annotated. Article III Section 2
2
Office of the Law Revision Counsel. 28 U.S. Code 1332 – Diversity of Citizenship; Amount in Controversy; Costs
3
Constitution Annotated. Citizenship of Natural Persons and Corporations
4
Legal Information Institute. Exxon Mobil Corp. v. Allapattah Services, Inc.
5
Office of the Law Revision Counsel. 28 U.S. Code 1441 – Removal of Civil Actions
6
Office of the Law Revision Counsel. 28 U.S. Code 1446 – Procedure for Removal of Civil Actions
7
Legal Information Institute. Ankenbrandt v. Richards, 504 U.S. 689 (1992)
8
Office of the Law Revision Counsel. 28 U.S. Code 1447 – Procedure After Removal Generally