The Motion to Dismiss: Rule 12(b)(6) and the Plausibility Standard

American civil litigation has a gate at its entrance, and a great deal of effort is expended on both sides of it. Before a defendant must produce a single document, sit for a deposition or spend a dollar on electronic discovery, it is entitled to say to the court: even if everything in this complaint is true, it does not state a claim on which relief can be granted. That is a motion to dismiss under Rule 12(b)(6) of the Federal Rules of Civil Procedure, and in a system where the losing party ordinarily pays none of the winner's legal fees and discovery routinely costs more than the claim is worth, getting through the gate is often the whole battle.

English practitioners will recognise something of their own strike-out jurisdiction here, but the resemblance is imperfect and the differences matter. The American motion is made earlier, is decided on the pleadings alone, is granted in part far more often than in whole, and — critically — carries no costs consequence for the party that loses it.

This guide sets out what the modern pleading standard requires, what else a Rule 12 motion can raise, what material the court may look at, and how a plaintiff should respond to a motion that has some merit.

The pleading standard, and how it changed

Rule 8(a)(2) requires no more than "a short and plain statement of the claim showing that the pleader is entitled to relief". For half a century that was read through Conley v. Gibson, 355 U.S. 41 (1957), which held that a complaint should not be dismissed unless it appeared beyond doubt that the plaintiff could prove no set of facts in support of his claim entitling him to relief. That formulation was extraordinarily permissive: virtually any complaint survived it.

Two Supreme Court decisions replaced it. In Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007), an antitrust conspiracy case, the Court held that a complaint must contain factual allegations sufficient to raise a right to relief above the speculative level and to state a claim that is plausible on its face. It expressly retired the "no set of facts" language. Two years later, in Ashcroft v. Iqbal, 556 U.S. 662 (2009), the Court confirmed that the plausibility standard applies to all civil actions, not merely to antitrust, and set out the analysis courts now perform.

That analysis has two steps.

Identify and disregard the legal conclusions. Allegations that merely recite the elements of a cause of action, or assert in terms that the defendant acted knowingly, negligently or in breach of duty, are not entitled to the assumption of truth. A pleading that says "the defendant conspired to fix prices" has alleged a conclusion, not a fact.
Assume the truth of the well-pleaded factual allegations and ask whether they plausibly give rise to an entitlement to relief. This, the Court said, is a context-specific task requiring the reviewing court to draw on its judicial experience and common sense.

Plausibility is not probability. The plaintiff need not show that his version is more likely than the defendant's. But it demands more than a sheer possibility that the defendant acted unlawfully, and where the facts pleaded are equally consistent with lawful conduct, the complaint will generally fail.

Heightened standards

Rule 9(b) requires that in alleging fraud or mistake, a party must state with particularity the circumstances constituting it — which the courts of appeals have reduced to the who, what, when, where and how of the alleged fraud. Malice, intent, knowledge and other conditions of mind may be alleged generally, though Iqbal has tightened what "generally" permits in practice. Securities fraud claims face a further statutory layer under the Private Securities Litigation Reform Act, including a requirement to plead facts giving rise to a strong inference of scienter.

The other defences in Rule 12

Rule 12(b) is not only about the sufficiency of the pleading. It collects a set of threshold defences, and a defendant must handle them together or risk losing them.

12(b)(1) — lack of subject-matter jurisdiction. Federal courts are courts of limited jurisdiction. This defence cannot be waived and may be raised at any time, including by the court on its own motion.
12(b)(2) — lack of personal jurisdiction. Whether the court has power over this defendant at all: the analysis is set out in our guide to personal jurisdiction in US courts.
12(b)(3) — improper venue, and its close relative, the motion to transfer.
12(b)(5) — insufficient service of process.
12(b)(7) — failure to join a party under Rule 19.

Rule 12(g) and 12(h) contain the consolidation trap. A defendant who makes a Rule 12 motion and omits an available defence of personal jurisdiction, venue, process or service waives it. Those four must be raised in the first Rule 12 motion or in the answer, whichever comes first. Failure to state a claim and failure to join are more forgiving and may be raised later; subject-matter jurisdiction never expires.

What the court may look at

The motion is decided on the pleadings. The court accepts the complaint's well-pleaded facts as true and draws reasonable inferences in the plaintiff's favour. It may also consider documents attached to the complaint, documents incorporated into it by reference, documents integral to the claim and whose authenticity is not disputed — the contract sued upon, typically — and matters of which judicial notice may properly be taken, such as public filings and court records.

Anything beyond that changes the nature of the motion. Under Rule 12(d), if matters outside the pleadings are presented and not excluded by the court, the motion must be treated as one for summary judgment under Rule 56, and all parties must be given a reasonable opportunity to present pertinent material. Defence counsel who attach a declaration disputing the facts have generally made a mistake: a motion to dismiss is not the place to argue that the plaintiff's account is untrue.

Timing, and the plaintiff's most useful right

A defendant served in the United States generally has twenty-one days to respond to a complaint, and filing a Rule 12 motion suspends the time to answer until the court rules. Stipulated extensions are commonplace, and waiver of service under Rule 4(d) buys the defendant a longer period.

The plaintiff's most valuable procedural right sits in Rule 15(a)(1)(B): a party may amend its pleading once as a matter of course within twenty-one days after service of a Rule 12(b) motion. No leave, no argument. A plaintiff whose complaint has genuine defects — and a motion to dismiss will usually identify them with some precision — should think hard about amending rather than defending. It costs nothing, it cures the problem, and it obliges the defendant to move again against a stronger pleading.

Beyond that first amendment, leave to amend is required, and Rule 15(a)(2) directs that the court should freely give leave when justice so requires. Courts commonly grant a dismissal "with leave to amend", and a dismissal without prejudice is not the end of the case. A dismissal with prejudice is, subject to appeal.

How the motion is actually used

The realistic assessment, which clients are not always given, is this. Complete dismissals of entire complaints are the exception. What motions to dismiss most often achieve is the removal of the weaker claims — the tacked-on fraud count, the claim for punitive damages, the count against the individual officers — narrowing the case before discovery begins. That narrowing has real economic value in a system where discovery cost is the plaintiff's principal source of leverage.

Against that, the motion has costs. It is briefed at length, it can take months to decide, and it educates the plaintiff about the weaknesses in his own pleading at a stage when he can still fix them without consequence. A defendant with a strong factual defence but a plaintiff whose pleading is competent may do better to answer, take the case to discovery, and move for summary judgment on a record.

The absence of costs-shifting is central to all of this. In England, an unsuccessful application carries the other side's costs, which disciplines both the making and the resisting of interlocutory applications. Under the American Rule each party bears its own fees absent a statute or contract providing otherwise, so a defendant loses nothing but its own money by trying, and a plaintiff who defeats the motion recovers nothing for having done so. Our guide to costs orders sets out how differently the common law jurisdictions treat this question.

Responding to the motion

Read the motion as a critique of the pleading, not an attack on the case. If the criticism is right, amend within the twenty-one days and move on.
Plead facts, not characterisations. Dates, documents, names, sums, sequences. The most common reason complaints fail Iqbal is that they assert what the defendant did wrong without saying what the defendant did.
Do not rely on material outside the complaint in opposition without addressing Rule 12(d). Attaching a declaration to save a defective complaint invites conversion to summary judgment before any discovery has been taken.
Ask for leave to amend in the alternative. A plaintiff who says nothing about amendment may find the dismissal entered with prejudice.

For the sequence that follows if the case survives — and it is the phase that decides most American litigation — see our guide to discovery in US civil litigation. If you have just been served and are working out what your response options are, our guide to responding to a lawsuit in the US covers the ground. For the equivalent jurisdiction in England, Hong Kong and Singapore, see striking out and summary judgment.

If you need to test a complaint against the plausibility standard, or work out which Rule 12 defences must be raised now or lost, CommonBench's Legal Chat can take you through the rules and the authorities.

This article is published by CommonBench for informational purposes only and does not constitute legal advice. If you are drafting or answering a complaint in US federal court and need to test it against Twombly and Iqbal, try CommonBench — AI-powered legal research with verified citations across five common law jurisdictions.