Sullivan & Cromwell apologises after AI hallucinations appear in court document

Elite firm left red-faced

One of the US’s most prestigious law firms has apologised to a New York judge after AI-hallucinated citations were found in a court filing it had submitted.

In a letter to Judge Martin Glenn, Andrew Dietderich, co-head of global restructuring at Sullivan & Cromwell, said “we deeply regret that this has occurred.” He acknowledged that the firm’s 9 April filing contained AI-generated “hallucinations” and other errors.

The blunder came to light in high-profile proceedings linked to the Prince Group fraud saga, in which US prosecutors have charged the owner with offences including wire fraud and money laundering. US outfit Boies Schiller Flexner, acting on the other side, flagged the issues, telling the court that S&C’s motion misquoted the Bankruptcy Code, misdescribed authorities, and even cited a case that did not exist.

In his letter, Dietderich admitted that the firm’s internal AI policies had not been followed. S&C’s guidance requires lawyers to rigorously verify any AI-generated material.

The firm says it has since taken “immediate remedial measures”, including re-reviewing all the filings in the matter and submitting a corrected version of the motion. It has not disclosed which lawyers were responsible, nor whether any internal disciplinary action has been taken.

This slip-up is a slightly awkward one given S&C’s position at the top of the legal market. The firm is among the most profitable in the world, with profits per equity partner sitting at around £5 million, while senior partner rates can reportedly exceed £2,000 an hour.

This latest error joins a growing list of AI-related mishaps across the profession. Legal Cheek readers may recall our reports on an Australian lawyer using ChatGPT to generate inaccurate case filings, as well as a High Court judge’s anger at a rookie barrister for relying on fake authorities.

Sullivan & Cromwell has been approached for comment.