Sullivan & Cromwell Forced to Apologize to Federal Judge After AI Hallucinations Contaminated Court Filing with 40 False Citations

Sullivan & Cromwell, one of Wall Street's most prominent law firms, has issued a formal apology to Chief Judge Martin Glenn of the U.S. Bankruptcy Court for the Southern District of New York after submitting a court filing riddled with approximately 40 incorrect citations and additional errors directly attributable to AI-generated hallucinations.

The admission came in a letter from Andrew Dietderich, co-head of Sullivan & Cromwell's global restructuring team, who acknowledged the firm's responsibility under Local Bankruptcy Rule 9011-1(d). "We deeply regret that this has occurred," Dietderich wrote, taking direct personal responsibility for the failure. The problematic filing was an emergency motion submitted nine days prior to the apology, placing the firm in the uncomfortable position of correcting its own work before a federal tribunal.

The incident underscores the documented risks of deploying generative AI tools in high-stakes legal contexts without adequate verification protocols. Legal professionals have long warned that large language models can produce convincing but entirely fabricated case citations—a phenomenon known in the industry as "hallucination." Sullivan & Cromwell's submission reportedly contained multiple false precedents that appeared legitimate on their surface. The episode is likely to intensify scrutiny of AI adoption practices across major law firms, with courts and regulators watching closely for how the legal profession establishes safeguards when machine-generated content enters official proceedings.