Sullivan & Cromwell apologizes for AI errors in filing

Sullivan & Cromwell apologized to a federal judge after an emergency bankruptcy filing submitted to the U.S. Bankruptcy Court for the Southern District of New York contained about 40 incorrect citations and other errors produced by AI hallucinations, the firm wrote in a letter to Chief Judge Martin Glenn.

Andrew Dietderich, co-head of the firm’s global restructuring group, wrote that the emergency motion was filed nine days before the letter and included inaccurate citations and other mistakes that should have been caught under Local Bankruptcy Rule 9011-1(d).

He wrote, “We deeply regret that this has occurred,” and accepted responsibility for the failures.

Dietderich noted the firm has policies governing the use of AI tools that require review of citations, but those procedures were not followed in this case. “Regrettably, this review process did not identify the inaccurate citations generated by AI, nor did it identify other errors that appear to have resulted in whole or in part from manual error,” he wrote.

The errors were identified after a rival law firm reviewed the emergency filing; Dietderich said he called the other firm to thank them for bringing the problems to the firm’s attention and to apologize directly.

Sullivan & Cromwell said it took immediate remedial steps, notified the court and opened an internal investigation into how the inaccurate filing occurred. The firm added it is reviewing the circumstances and is evaluating whether additional changes to its training and review processes are warranted.

A database maintained by legal technologist Damien Charlotin has recorded 1,334 instances of AI hallucinations in court filings worldwide, including more than 900 in the United States. Most entries involve fabricated citations, and some filings include AI-generated legal arguments.

Sullivan & Cromwell is one of the largest U.S. law firms by revenue and ranked 30th on the AmLaw Global 200. The firm has represented high-profile clients, including the crypto exchange FTX in its bankruptcy proceedings.

The letter to the court and the firm’s internal review followed the discovery of the errors.