Rule 11 sanctions for AI-generated citations
What Federal Rule of Civil Procedure 11 says, how often public AI-hallucination decisions mention it next to other sanction bases, and the amounts recorded. Rule text read on ; counts computed from the corpus refreshed 2026-10-22.
In the corpus
127 of 2,202 public records (5.8%) mention Rule 11.A record counts as mentioning a basis when its summary, outcome, lesson or hallucination-items text names it (patterns in lib/rule-11.ts), counted from the same public corpus file the case pages use. A mention is not proof that a court sanctioned under that basis: some records say the court declined to apply it. Latest tracked decision: 2026-10-15.
What Rule 11 says
Fed. R. Civ. P. 11(b), quoted from the Legal Information Institute page read on October 22, 2026. The same rule is published by the Administrative Office of the U.S. Courts.
By presenting to the court a pleading, written motion, or other paper—whether by signing, filing, submitting, or later advocating it—an attorney or unrepresented party certifies that to the best of the person's knowledge, information, and belief, formed after an inquiry reasonable under the circumstances:
(1) it is not being presented for any improper purpose, such as to harass, cause unnecessary delay, or needlessly increase the cost of litigation;
(2) the claims, defenses, and other legal contentions are warranted by existing law or by a nonfrivolous argument for extending, modifying, or reversing existing law or for establishing new law;
(3) the factual contentions have evidentiary support or, if specifically so identified, will likely have evidentiary support after a reasonable opportunity for further investigation or discovery; and
(4) the denials of factual contentions are warranted on the evidence or, if specifically so identified, are reasonably based on belief or a lack of information.
Sanctions, Rule 11(c), in part:
(c)(1) If, after notice and a reasonable opportunity to respond, the court determines that Rule 11(b) has been violated, the court may impose an appropriate sanction on any attorney, law firm, or party that violated the rule or is responsible for the violation.
(c)(2) … The motion must be served under Rule 5, but it must not be filed or be presented to the court if the challenged paper, claim, defense, contention, or denial is withdrawn or appropriately corrected within 21 days after service or within another time the court sets.
(c)(4) A sanction imposed under this rule must be limited to what suffices to deter repetition of the conduct or comparable conduct by others similarly situated. The sanction may include nonmonetary directives; an order to pay a penalty into court; or, if imposed on motion and warranted for effective deterrence, an order directing payment to the movant of part or all of the reasonable attorney's fees and other expenses directly resulting from the violation.
Rule 11 reaches an attorney, a law firm or a party, including an unrepresented one. A fabricated citation is a legal contention with no support in existing law, which is why it is usually analyzed under (b)(2).
Rule 11 against other sanction bases
Records in the corpus whose text names each basis. A record can name several.
| Basis named in the record | Records |
|---|---|
| Rule 11 | 127 |
| Court's inherent power or authority | 9 |
| 28 U.S.C. § 1927 | 5 |
| Rule 37 | 4 |
| Rule 11, § 1927 and inherent authority together | 3 |
Section 1927 reads: "Any attorney or other person admitted to conduct cases in any court of the United States or any Territory thereof who so multiplies the proceedings in any case unreasonably and vexatiously may be required by the court to satisfy personally the excess costs, expenses, and attorneys’ fees reasonably incurred because of such conduct." (law.cornell.edu, read October 22, 2026). It reaches the lawyer personally and requires unreasonable and vexatious multiplication of proceedings, which is why it is cited less often.
What the 127 Rule 11 records list as outcomes
| Outcome type (a record can list several) | Records |
|---|---|
| Warning | 51 |
| No sanction recorded | 26 |
| Monetary sanction or costs | 33 |
| Order to show cause | 11 |
| Bar referral | 8 |
| Filing struck | 5 |
| Case or appeal dismissed | 12 |
Amounts. 23 of these records carry a USD figure above $1. The range is $250 to $85,567, with a median of $1,500. 2 further records list a nominal $1 on a fee-shifting order; they are left out of the range because the figure is not a measured amount. The recorded figure is the total in the record and may combine Rule 11 with other bases or with fee awards. Each case page links the court document or news source.
Three records to read first
Mata v. Avianca: timeline from the court docket · Browse records by consequence
Before you rely on this
Counts reflect what each record's text says, not a reading of the underlying orders, and they are not usage-adjusted rates. Some records mention a state-court analogue of Rule 11. Confirm the current rule text on the uscourts.gov rules page and read the order itself before citing a decision. Nothing here is legal advice.
Primary sources (read October 22, 2026)
Questions this page answers
- Does Rule 11 apply to AI-generated fake citations?
- Rule 11(b) applies to any paper an attorney or unrepresented party presents to a federal court. By presenting it, the signer certifies that the legal contentions are warranted by existing law or a nonfrivolous argument, after an inquiry reasonable under the circumstances. The rule does not mention AI; courts apply it to citations to cases that do not exist.
- How many AI hallucination cases mention Rule 11?
- 127 of the 2,202 public records in the AI Vortex corpus (5.8%) mention Rule 11 in their summary, outcome, lesson or hallucination-items text, counted by script on the corpus refreshed 2026-10-22. A mention does not prove a sanction: some records say the court declined to apply the rule.
- What sanctions do courts impose under Rule 11 for fabricated citations?
- Rule 11(c)(4) limits a sanction to what suffices to deter repetition and allows nonmonetary directives, a penalty paid into court or payment of the movant's fees. Among the 127 records that mention Rule 11, 51 list a warning and 33 list a monetary sanction. 23 of those carry a USD amount above $1, from $250 to $85,567, median $1,500.
- What other bases do courts cite besides Rule 11?
- In the same corpus, 5 records mention 28 U.S.C. § 1927, 9 mention the court's inherent power or authority and 4 mention Rule 37. 3 mention Rule 11, § 1927 and inherent authority together. Rule 11 is named far more often than the other bases.
- Is there a safe harbor under Rule 11?
- For a motion for sanctions, yes. Rule 11(c)(2) says the motion must be served but not filed if the challenged paper is withdrawn or appropriately corrected within 21 days after service, or within another time the court sets. The safe harbor does not apply when a court acts on its own initiative under Rule 11(c)(3).