A U.S. federal judge has denied Sony Music Entertainment’s request to dramatically expand its copyright infringement lawsuit against AI music platform Udio, ruling that adding more than 30,000 additional sound recordings at this stage of the case would unnecessarily delay the legal proceedings.

Sony had asked the court for permission to amend its complaint by adding 30,442 copyrighted recordings, arguing that the additional works were identified during the discovery process after gaining greater access to Udio’s AI training data. The label alleged that the recordings had been copied and used to train Udio’s generative AI models without authorization.

However, Judge Alvin K. Hellerstein rejected the request, explaining that expanding the case so significantly near the end of discovery would require extensive new evidence, additional document production, and further legal disputes. According to the court, doing so would substantially broaden the scope of the lawsuit and delay resolution of the central legal questions surrounding AI training and copyright law.

The ruling means the lawsuit will continue with the 333 sound recordings already included in the case rather than the tens of thousands Sony sought to add. Importantly, the judge did not rule on whether Udio infringed Sony’s copyrights or whether AI training qualifies as fair use. Instead, the decision focused solely on case management and keeping the litigation on schedule.

Sony remains the only major record company actively pursuing litigation against Udio after other major labels reached separate agreements with the AI music platform. Despite this setback, the company still has the option to pursue claims involving the additional recordings through separate legal actions if it chooses.

The lawsuit is one of several landmark legal battles shaping the future relationship between the music industry and artificial intelligence. Record labels argue that AI developers cannot train commercial music-generation systems on copyrighted recordings without permission, while AI companies maintain that aspects of the training process may qualify as fair use under U.S. copyright law.

As the case moves forward, the court is expected to focus on the broader legal questions surrounding copyright, licensing, and AI-generated music issues that could have far-reaching implications for artists, record labels, technology companies, and the future of generative AI across the music industry.