Sullivan & Cromwell apologized to a federal judge after submitting a court filing that contained roughly 40 incorrect citations and other mistakes the firm traced to AI-generated hallucinations. Andrew Dietderich, co-head of the firm’s global restructuring group, wrote to Chief Judge Martin Glenn of the U.S. Bankruptcy Court for the Southern District of New York, saying the firm “deeply regret[s]” the errors and accepting responsibility for failing to ensure accuracy under Local Bankruptcy Rule 9011-1(d).
Dietderich said the firm has policies governing the use of AI tools, including a citation-review process, but those procedures were not followed in this case. He added that the review did not catch the inaccurate citations produced by AI and that some errors appear to have stemmed, at least in part, from manual mistakes. The mistakes appeared in an emergency motion filed nine days earlier.
The incident highlights the danger of relying on AI-assisted drafting in high-stakes legal work when oversight breaks down. Legal technologist Damien Charlotin has compiled a database documenting 1,334 incidents of AI hallucinations in court filings worldwide, with more than 900 reported in the U.S. Most of those reports involve fabricated citations; some also include AI-generated legal arguments.
Sullivan & Cromwell said it took immediate remedial steps and launched a full review to determine how the errors occurred. The firm is considering additional training and enhancements to its internal review processes. Dietderich also said rival counsel at Boies Schiller Flexner LLP alerted the firm to the inaccuracies; he called them to thank them for flagging the problems and to apologize.
Sullivan & Cromwell, one of the largest U.S. law firms by revenue and ranked 30th on the AmLaw Global 200, has handled major matters including the bankruptcy of crypto exchange FTX. The firm is conducting an internal investigation and said it will consider further measures to prevent similar AI-related errors in future filings.