Sony Music moves to add more than 30,000 copyrighted recordings to its lawsuit against Udio

Sony Music Entertainment has asked a federal court for permission to expand its copyright infringement lawsuit against AI music generator Udio, seeking to add over 30,000 copyrighted sound recordings to its complaint.

The motion, filed on Friday (May 22) in the US District Court for the Southern District of New York, says Sony identified the additional works after gaining access to Udio‘s training data during the discovery process.

Sony Music, along with co-plaintiffs Arista Music and Arista Records, is now the sole remaining major label plaintiff in the case, after Universal Music Group settled its claims against Udio in October 2025 and Warner Music Group followed suit in November 2025.

According to the filing, which you can read here, the proposed Second Amended Complaint “asserts 30,442 copyrighted works which Udio copied and ingested into its generative AI models.”

“Plaintiffs identified these additional works in discovery once granted access to Udio‘s training data,” the motion states.

“Plaintiffs identified these additional works in discovery once granted access to Udio‘s training data.”

Sony Music’s Motion

The plaintiffs argue that the court should grant the amendment because they “were diligent in identifying the additional works” and “there is no question that Plaintiffs have a viable claim for direct copyright infringement.”

The motion adds that allowing the amendment “will not prejudice Udio,” noting that it would at most require an extension of the document production deadline, which is currently set to close on June 26, 2026.

Alternatively, the plaintiffs suggest the court could grant leave to amend and stay ownership-related discovery on the new works until after both sides have submitted motions for summary judgment on the fair use question.

The motion marks a potentially significant expansion of Sony Music‘s case against the AI startup.

All three major record companies – Sony, UMG, and Warner – originally sued Udio and rival AI platform Suno in June 2024, accusing both companies of “mass infringement” of copyright.

In August 2024, Udio and Suno largely admitted that they had used copyrighted recordings to train their AI models, but argued their use fell under the “fair use” exemption to US copyright law.

The labels then amended their complaint in September 2025 to add a Digital Millennium Copyright Act claim, alleging that Udio circumvented YouTube‘s technological protections to collect copyrighted recordings for use as training data.

UMG and Warner subsequently struck licensing deals with Udio for a new AI music platform set to launch in 2026. On Monday (May 25), it was reported that Udio‘s forthcoming licensed AI music platform will be called Starstruck.

The latest filing arrives weeks after two developments that further shaped the case.

On April 15, Judge Alvin K. Hellerstein denied Udio‘s motion to dismiss Sony‘s DMCA circumvention claim, finding that the plaintiffs had “plausibly allege[d] that YouTube employs technological measures that regulate access to its content and that Defendant circumvented them.”

The judge noted, however, that whether YouTube‘s measures ultimately constitute access controls “requires a greater factual record than the pleadings contain.”

Then, on April 29, Udio filed its answer to Sony Music‘s amended complaint, admitting that it “obtained audio data from YouTube for use as training data” and that it had used YT-DLP – described in the case as a stream-ripping tool – to acquire some of that data.

Udio maintained its fair use defense, calling its AI tool’s back-end process “quintessential fair use,” and accused Sony of “anticompetitive activities that extend an unlawful monopoly over the production and commercialization of music”.Music Business Worldwide