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Incident Tracker / United States (state)

Deutsche Bank Natl. Trust Co. v. LeTennier, 2026 NY Slip Op 00040 (App. Div. 3d Dept.)

·New York Supreme Court, Appellate Division, Third Department·US-STATESanctions

In what it called the first New York appellate decision addressing generative-AI sanctions, the Third Department fined defense counsel Joshua Douglass $7,500 and the defendant $2,500 under 22 NYCRR 130-1.1 after briefs contained 23 fabricated cases and counsel kept filing fake authorities after being alerted — a state intermediate-appellate precedent-setter.

Court
New York Supreme Court, Appellate Division, Third Department
Date
2026-01-08
Who used the AI
Not recorded
AI tool
generative AI (unspecified)
Conduct
Defense counsel filed appellate briefs, motions, and letters containing no fewer than 23 fabricated cases across five filings, plus numerous misrepresentations of real cases, and continued to add fake authorities after being alerted.
Outcome
Sanctions
Penalty
US$10,000
Regulatory outcome
No separate regulatory disposition recorded
Status
Verified against listed sources
Last checked
2026-09-04

What was fabricated or misused

  • No less than 23 fabricated cases across five appellate filings — the court did not list all names
  • Tishman Realty & Construction Co. v Regan — fake case name with a New York citation and a CPLR 5015 proposition; the citation led to a different Illinois case
  • Several real cases — holdings misrepresented as dispositive in the appellant's favor when they were not

What the court said

“Here, defendant submitted at least 23 fabricated legal authorities across five filings during the pendency of this appeal.”
New York Supreme Court, Appellate Division, Third Department, slip op. at *5
“It is axiomatic that submission of fabricated legal authorities is completely without merit in law and therefore constitutes frivolous conduct”
New York Supreme Court, Appellate Division, Third Department, slip op. at *5
“To be clear, attorneys and litigants are not prohibited from using GenAI to assist with the preparation of court submissions.”
New York Supreme Court, Appellate Division, Third Department, slip op. at *7

Timeline

  1. Supreme Court denied LeTennier's CPLR 5015 motion and warned against continued frivolous conduct.
  2. Supreme Court struck more than 20 documents and required future applications by order to show cause.
  3. Supreme Court declined to sign LeTennier's latest order to show cause.
  4. The Third Department heard argument, where counsel conceded using AI to prepare papers.
  5. The appellate court affirmed the orders and imposed $10,000 in total sanctions.

Why this case matters

Deutsche Bank supplies a state appellate benchmark rather than another trial-court Rule 11 order. The Third Department described it as the first New York appellate decision on GenAI sanctions and compared the number and persistence of fake authorities with Noland, Mid Central v HoosierVac and Kruse. Unlike Sullivan & Cromwell Prince Global, where the firm disclosed and corrected before a ruling, LeTennier involved repeated filings after notice and an appeal the court also found frivolous. The split sanction, $7,500 for counsel and $2,500 for the client, ties AI misuse to broader vexatious litigation controls.

Practice note

New York appellate counsel should treat every AI-suggested authority as unfiled until it has been opened in an official reporter or database and checked against the proposition in the brief. Once an opponent or court flags a false citation, the next filing should withdraw the material, correct the record and explain the source. Adding new authorities without a full cite-check turned the problem into sanctionable persistence.

Primary sources for this incident

Related regulation records for this incident

No related regulation record has been linked to this incident yet.

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Cite this record

SafeLegalAI Global Legal AI Incident Tracker, “Deutsche Bank Natl. Trust Co. v. LeTennier, 2026 NY Slip Op 00040 (App. Div. 3d Dept.)”, safelegalai.com/tracker/deutsche-bank-v-letennier (accessed 2026-09-16). Data: CC BY 4.0.

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