UBE Subject Matter Jurisdiction
Last updated: May 2, 2026
Subject Matter Jurisdiction questions are one of the highest-leverage areas to study for the UBE. This guide breaks down the rule, the elements you need to recognize, the named traps that catch most students, and a memory aid that scales to test day. Read it once, then practice the same sub-topic adaptively in the app.
The rule
A federal district court may hear a case only if it has subject matter jurisdiction (SMJ), which is conferred by Article III and a federal statute. The two principal grants are federal question jurisdiction under 28 U.S.C. § 1331 (claim must arise under federal law on the face of the well-pleaded complaint) and diversity jurisdiction under 28 U.S.C. § 1332 (complete diversity of citizenship between all plaintiffs and all defendants AND amount in controversy exceeding $75,000, exclusive of interest and costs). Supplemental jurisdiction under 28 U.S.C. § 1367 reaches additional claims that share a common nucleus of operative fact with a claim already within original jurisdiction, subject to § 1367(b)'s carve-out in diversity cases. SMJ is non-waivable and may be raised by any party — or sua sponte by the court — at any time, including for the first time on appeal.
Elements breakdown
Federal Question Jurisdiction (28 U.S.C. § 1331)
Federal district courts have original jurisdiction over civil actions arising under the Constitution, laws, or treaties of the United States.
- Federal issue appears on face of well-pleaded complaint
- Federal law creates the cause of action, OR
- State-law claim necessarily raises substantial, disputed federal issue
- Federal jurisdiction will not disrupt federal-state balance
- Anticipated federal defenses do NOT count
Common examples:
- § 1983 civil rights action
- Federal antitrust claim under Sherman Act
- Patent infringement under Title 35
- Grable-style embedded federal issue in quiet-title action
Diversity Jurisdiction (28 U.S.C. § 1332(a)(1))
Federal courts have original jurisdiction over civil actions between citizens of different states where the amount in controversy exceeds $75,000.
- Complete diversity at filing — no plaintiff shares citizenship with any defendant
- Amount in controversy exceeds $75,000, exclusive of interest and costs
- Plaintiff's good-faith claim controls amount unless legally certain otherwise
- Citizenship measured at time complaint is filed
Common examples:
- Tort suit between New York plaintiff and Texas defendant for $200,000
- Contract dispute between Ohio LLC member-citizens and California defendant
Citizenship of Parties
Citizenship rules differ by party type and govern whether complete diversity exists.
- Natural person: state of domicile (physical presence + intent to remain indefinitely)
- Corporation: every state of incorporation AND principal place of business (nerve center test, Hertz)
- Unincorporated association/LLC/partnership: citizenship of every member or partner
- Decedent's estate, infant, incompetent: citizenship of represented party, not representative (§ 1332(c)(2))
- U.S. citizen domiciled abroad: cannot sue or be sued in diversity (stateless)
Amount in Controversy
The plaintiff's good-faith pleading controls unless it appears to a legal certainty the claim is for $75,000 or less.
- A single plaintiff may aggregate all claims against a single defendant
- Multiple plaintiffs cannot aggregate unless asserting a common, undivided interest
- Joint and several liability claims may be aggregated against multiple defendants
- Injunctive relief valued by either-viewpoint rule (cost or benefit)
- Interest and costs are excluded; attorney's fees included only if statute or contract authorizes
Supplemental Jurisdiction (28 U.S.C. § 1367)
District courts with original jurisdiction over one claim may hear additional claims forming part of the same case or controversy.
- Anchor claim has original (federal question or diversity) jurisdiction
- Supplemental claim shares common nucleus of operative fact (§ 1367(a))
- § 1367(b) bar: in diversity cases, no supplemental jurisdiction over claims by plaintiffs against persons made parties under Rules 14, 19, 20, or 24 if it would destroy complete diversity
- Court may decline under § 1367(c) (novel state issue, state claim predominates, all federal claims dismissed, exceptional circumstances)
Removal Jurisdiction (28 U.S.C. §§ 1441, 1446, 1447)
A defendant may remove a state-court action to federal court if the federal court would have had original jurisdiction.
- Notice of removal filed within 30 days of service of removable pleading
- All properly served defendants must consent (rule of unanimity)
- Diversity removal barred if any defendant is citizen of forum state (§ 1441(b)(2) — forum-defendant rule)
- Diversity removal barred more than 1 year after commencement absent bad faith
- Plaintiff's motion to remand for non-SMJ defect must be filed within 30 days; SMJ defects raisable any time before final judgment
Non-Waivability and Timing
Subject matter jurisdiction limits the court's power and cannot be created by consent or waived.
- Court must dismiss sua sponte if SMJ lacking (Rule 12(h)(3))
- Defect raisable by any party at any time, including on appeal
- Parties cannot stipulate to SMJ
- Distinguish from personal jurisdiction, which IS waivable
Common patterns and traps
The Well-Pleaded Complaint Filter
Federal question jurisdiction depends only on what the plaintiff must allege to state her claim — not on what the defendant will argue in response. A state-law contract suit in which the defendant plans to raise a federal preemption defense is NOT a § 1331 case. Likewise, a federal counterclaim does not support § 1331 jurisdiction over the plaintiff's state-law complaint. The MBE loves this distinction because it's intuitively wrong.
Vignette describes a state-law claim and a clearly federal defense; a tempting wrong choice says federal jurisdiction exists 'because federal law will be at issue.'
The LLC/Partnership Citizenship Trap
Unincorporated entities (LLCs, partnerships, LLPs, unions) take the citizenship of every member or partner — not the state of formation, not a 'principal place of business.' Only true corporations get the dual-citizenship rule of § 1332(c)(1). Bar examiners routinely plant a member whose citizenship destroys diversity, knowing test-takers will instinctively apply the corporation rule.
Choice that treats an LLC like a corporation ('citizen of Delaware where formed and California where headquartered') and finds diversity satisfied.
The Aggregation Mismatch
A single plaintiff may aggregate any and all claims against a single defendant to reach $75,000, even unrelated claims. But two plaintiffs cannot aggregate their separate claims, and a single plaintiff cannot aggregate against multiple defendants unless they are jointly liable on a single, indivisible obligation. The trap presents class-action-flavored facts and asks whether plaintiffs can pool claims.
Two plaintiffs each suffered $50,000 damages from same defendant; wrong choice aggregates to $100,000 and finds diversity satisfied.
The § 1367(b) Carve-Out
Supplemental jurisdiction is broad in federal-question cases but narrow in diversity cases. Section 1367(b) blocks plaintiffs from using supplemental jurisdiction against persons made parties under Rules 14, 19, 20, or 24 when doing so would destroy complete diversity. The bar tests this with a third-party impleader scenario — the plaintiff tries to assert a direct claim against the impleaded non-diverse third-party defendant.
Plaintiff in a diversity case asserts a claim against a third-party defendant impleaded by the original defendant; wrong choice finds supplemental jurisdiction proper.
The Forum-Defendant Removal Bar
Even when complete diversity and the jurisdictional amount exist, § 1441(b)(2) prohibits removal of a diversity case if any properly joined and served defendant is a citizen of the state in which the action was filed. This bar applies only to diversity removal, not to federal-question removal. Test-takers see diversity, see the amount, and click 'removable' without checking the forum-defendant rule.
Plaintiff sues two defendants — one out-of-state, one in-forum — in state court for $200,000 in tort; wrong choice allows removal because complete diversity exists.
How it works
Start every federal civil-procedure question by asking: does the federal court have power to hear this case? If the complaint pleads a federal cause of action — say, Reyes sues her employer under Title VII — § 1331 supplies federal question jurisdiction, full stop. If the claim is purely state-law (a slip-and-fall, a breach of contract), look to § 1332: are the parties completely diverse, and does the amount exceed $75,000? Imagine Liu, a New York domiciliary, sues Patel Imports, LLC for $90,000 in breach of contract. Patel Imports is an LLC with three members domiciled in New York, New Jersey, and Delaware. Diversity is destroyed — the New York member shares Liu's citizenship, and an LLC's citizenship follows every member. The case must be filed (or, if removed, remanded) to state court. Once you confirm an anchor claim, supplemental jurisdiction can pull in factually related claims, but watch § 1367(b): in a diversity case, a plaintiff cannot use § 1367 to assert a state-law claim against a non-diverse third-party defendant impleaded under Rule 14 — that would let the plaintiff smuggle in the very defect that complete diversity exists to prevent.
Worked examples
How should the court rule on the motion?
- A Deny the motion, because the LLC's citizenship is determined by its state of formation and principal place of business, both of which are diverse from Reyes.
- B Deny the motion, because the amount in controversy exceeds $75,000 and the LLC is a business entity registered in a state other than Nevada.
- C Grant the motion, because the LLC takes the citizenship of every one of its members, and one member is a citizen of Nevada, destroying complete diversity. ✓ Correct
- D Grant the motion, but only after allowing Reyes to amend the complaint to dismiss the Nevada-member-related allegations.
Why C is correct: For diversity purposes, an LLC takes the citizenship of every one of its members — not its state of formation or principal place of business. Because one member is a citizen of Nevada (the same state as Reyes), complete diversity is destroyed, and the court lacks subject matter jurisdiction under § 1332. The court must dismiss; SMJ defects cannot be cured by amendment that removes mere allegations rather than parties.
Why each wrong choice fails:
- A: This applies the corporate dual-citizenship rule of § 1332(c)(1) to an LLC. LLCs are unincorporated associations and take the citizenship of every member, regardless of where the entity was formed or headquartered. (The LLC/Partnership Citizenship Trap)
- B: Amount in controversy is satisfied, but it does not cure the citizenship defect. Both prongs of § 1332 — complete diversity AND amount over $75,000 — must be met. (The LLC/Partnership Citizenship Trap)
- D: You cannot 'amend away' a non-diverse member's citizenship by recasting allegations; the entity itself shares Reyes's citizenship. Dismissal of the non-diverse party would be required, which is not what this choice describes.
Does the court have subject matter jurisdiction?
- A Yes, because Liu's complaint expressly raises a federal preemption issue, which establishes federal question jurisdiction under § 1331.
- B Yes, because complete diversity exists between Liu and Patel Manufacturing and the amount in controversy exceeds $75,000. ✓ Correct
- C No, because federal question jurisdiction requires the federal issue to appear in the well-pleaded complaint, and a state-law claim is not removable to federal court.
- D No, because the well-pleaded complaint pleads only a state-law claim and the parties lack complete diversity.
Why B is correct: Diversity jurisdiction exists: Liu (Oregon) is completely diverse from Patel Manufacturing, a corporation that is a citizen of both Delaware (incorporation) and Washington (principal place of business under Hertz), and the $120,000 amount exceeds the $75,000 threshold. The anticipated federal preemption defense does NOT support § 1331 because federal jurisdiction depends on the well-pleaded complaint, not the defendant's anticipated defenses — but § 1332 supplies an independent basis here.
Why each wrong choice fails:
- A: The well-pleaded complaint rule bars federal question jurisdiction based on an anticipated defense. Even if Liu pleads the defense in his complaint, the federal issue must be part of his cause of action, not a predicted response. (The Well-Pleaded Complaint Filter)
- C: The well-pleaded complaint analysis is correct, but the conclusion ignores the independent diversity basis. SMJ analysis must consider every available statutory grant before dismissing.
- D: Complete diversity does exist — Patel Manufacturing is a corporation whose dual citizenship (Delaware and Washington) does not overlap with Liu's Oregon citizenship. (The LLC/Partnership Citizenship Trap)
How should the court rule?
- A Deny the motion, because Cordova's claim against Beaumont Trucking arises from the same accident as the anchor claim and falls within supplemental jurisdiction under § 1367(a).
- B Deny the motion, because once the federal court has jurisdiction over the original action, it has supplemental jurisdiction over all related claims regardless of citizenship.
- C Grant the motion, because § 1367(b) bars supplemental jurisdiction over a plaintiff's claim against a person made a party under Rule 14 when exercising jurisdiction would be inconsistent with § 1332's complete-diversity requirement. ✓ Correct
- D Grant the motion, because Cordova's $200,000 claim against Beaumont Trucking does not independently exceed $75,000 by enough margin to satisfy diversity standards.
Why C is correct: Section 1367(b) carves out supplemental jurisdiction in diversity cases over claims by plaintiffs against persons made parties under Rule 14, 19, 20, or 24 when doing so would be inconsistent with § 1332's complete-diversity requirement. Cordova (Florida) and Beaumont Trucking (Florida via its sole member) share citizenship; allowing Cordova's direct claim would destroy the very diversity § 1332 demands. The court must dismiss Cordova's claim against Beaumont, though Marlowe's third-party impleader claim remains.
Why each wrong choice fails:
- A: This correctly identifies § 1367(a)'s common-nucleus test but ignores § 1367(b)'s diversity-case carve-out. In a federal-question case the answer would be different, but in a diversity case the carve-out controls. (The § 1367(b) Carve-Out)
- B: This overstates supplemental jurisdiction. Section 1367(b) explicitly limits supplemental jurisdiction in diversity cases to prevent plaintiffs from circumventing the complete-diversity rule. (The § 1367(b) Carve-Out)
- D: The amount-in-controversy threshold is $75,000, and $200,000 plainly exceeds it; the choice invents a 'margin' requirement that does not exist. The actual defect is citizenship, not amount. (The Aggregation Mismatch)
Memory aid
For diversity, run the 'CADD' check: Complete diversity, Amount > $75K, Domicile at filing, Determine citizenship by entity type. For § 1331, ask 'Well-Pleaded Complaint?' — if the federal issue would only appear in a defense or counterclaim, no federal question jurisdiction.
Key distinction
Subject matter jurisdiction (court's power, non-waivable, raisable any time) versus personal jurisdiction (defendant's protection, waivable, must be raised in first Rule 12 motion or answer). Confusing the two is the single most-tested trap on the MBE — if a question says the parties 'agreed' that the federal court has jurisdiction, that consent works for personal jurisdiction but is irrelevant to SMJ.
Summary
Federal SMJ requires either a federal question on the face of the well-pleaded complaint (§ 1331) or complete diversity plus over $75,000 in controversy (§ 1332), with supplemental jurisdiction extending to factually related claims subject to § 1367(b)'s diversity carve-out.
Practice subject matter jurisdiction adaptively
Reading the rule is the start. Working UBE-format questions on this sub-topic with adaptive selection, watching your mastery score climb in real time, and seeing the items you missed return on a spaced-repetition schedule — that's where score lift actually happens. Free for seven days. No credit card required.
Start your free 7-day trialFrequently asked questions
What is subject matter jurisdiction on the UBE?
A federal district court may hear a case only if it has subject matter jurisdiction (SMJ), which is conferred by Article III and a federal statute. The two principal grants are federal question jurisdiction under 28 U.S.C. § 1331 (claim must arise under federal law on the face of the well-pleaded complaint) and diversity jurisdiction under 28 U.S.C. § 1332 (complete diversity of citizenship between all plaintiffs and all defendants AND amount in controversy exceeding $75,000, exclusive of interest and costs). Supplemental jurisdiction under 28 U.S.C. § 1367 reaches additional claims that share a common nucleus of operative fact with a claim already within original jurisdiction, subject to § 1367(b)'s carve-out in diversity cases. SMJ is non-waivable and may be raised by any party — or sua sponte by the court — at any time, including for the first time on appeal.
How do I practice subject matter jurisdiction questions?
The fastest way to improve on subject matter jurisdiction is targeted, adaptive practice — working questions that focus on your specific weak spots within this sub-topic, getting immediate feedback, and revisiting items you missed on a spaced-repetition schedule. Neureto's adaptive engine does this automatically across the UBE; start a free 7-day trial to see your sub-topic mastery climb in real time.
What's the most important distinction to remember for subject matter jurisdiction?
Subject matter jurisdiction (court's power, non-waivable, raisable any time) versus personal jurisdiction (defendant's protection, waivable, must be raised in first Rule 12 motion or answer). Confusing the two is the single most-tested trap on the MBE — if a question says the parties 'agreed' that the federal court has jurisdiction, that consent works for personal jurisdiction but is irrelevant to SMJ.
Is there a memory aid for subject matter jurisdiction questions?
For diversity, run the 'CADD' check: Complete diversity, Amount > $75K, Domicile at filing, Determine citizenship by entity type. For § 1331, ask 'Well-Pleaded Complaint?' — if the federal issue would only appear in a defense or counterclaim, no federal question jurisdiction.
What's a common trap on subject matter jurisdiction questions?
Treating LLC as corporation for citizenship purposes
What's a common trap on subject matter jurisdiction questions?
Counting anticipated federal defense as basis for § 1331
Ready to drill these patterns?
Take a free UBE assessment — about 25 minutes and Neureto will route more subject matter jurisdiction questions your way until your sub-topic mastery score reflects real improvement, not luck. Free for seven days. No credit card required.
Start your free 7-day trial