AI hallucinated — and now an elite law firm is profusely apologizing to a federal judge
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A lawyer from the elite law firm has apologized to a bankruptcy judge for AI errors. DAVID DEE DELGADO/Reuters 2026-04-21T21:15:00.281Z Share Copy link Email Facebook WhatsApp X LinkedIn Bluesky Threads lighning bolt icon An icon in the shape of a lightning bolt.
Impact Link Save Saved Read in app This story is available exclusively to Business Insider subscribers. Become an Insider and start reading now. Have an account? Log in. Wall Street firm Sullivan & Cromwell apologized for AI hallucinations in a court filing.
Partner Andrew Dietderich said the errors made it through despite firm policies on AI and reviews. Fake legal citations are on the rise as AI hallucinations make there way into court filings. AI-generated summary Summaries are generated by an AI model trained on Business Insider's articles. AI may make mistakes or provide inaccurate/incomplete information. We're unable to load that answer right now. Please try again. What are "AI hallucinations"? What impact do fake citations have in court? What are Sullivan & Cromwell's AI policies? How can lawyers prevent AI errors? How do AI errors affect legal credibility? A partner at the elite Wall Street law firm Sullivan & Cromwell wrote an apology letter to a federal bankruptcy judge for a court filing that contained AI hallucinations. Loading audio narration... Andrew Dietderich, co-head of Global Finance & Restructuring at the firm, said in the April 18 note that a prior filing contained inaccurate citations and other errors, including AI hallucinations."'Hallucinations' are instances in which artificial intelligence tools fabricate case citations, misquote authorities, or generate non-existent legal sources," Dietderich's letter said. "We deeply regret that this has occurred." A chart attached to the letter showed that the motion contained incorrect case names and numbers and apparently fabricated quotes from cases.Dietderich said the errors by Sullivan & Cromwell, which represented the bankrupt firm Prince Global Holdings, were caught by the law firm Boies Schiller Flexner, which represented creditors, and that he'd thanked them and apologized. He said Sullivan & Cromwell — a 140-year-old firm with more than 1,000 attorneys — has comprehensive policies when it comes to using AI and that there are safeguards to avoid this exact scenario. The firm's policies weren't followed, and the errors also made it past the firm's review process for citations, he said.Dietderich wrote to Manhattan-based Chief Judge Martin Glenn that he and the firm were "keenly aware of our responsibility to ensure the accuracy of all submissions." "I take responsibility for the failure to do so," he said, adding they would submit a corrected version of the filing.A representative for the firm and Dietderich did not respond to inquiries from Business Insider. A representative for the judge also did not respond. When it comes to AI hallucinations in legal work, Sullivan & Cromwell has company.Fake legal citations have become more common since 2023, according to legal researcher Damien Charlotin, who keeps a public database of AI hallucinations in legal cases.