A federal judge has vacated an order that kept portions of Sony Music Entertainment‘s copyright lawsuit against AI music platform Udio under seal.
Judge Alvin K. Hellerstein, of the US District Court for the Southern District of New York, issued the ruling on Wednesday (June 3).
It reopens the question of how much of the material that Udio has designated confidential will stay off the public docket.
In a one-page order, which you can read here, Judge Hellerstein wrote: “My Order granting Defendants’ motion to seal, ECF No. 166, is hereby vacated.”
“The parties may brief that motion to seal, ECF No. 163, in the ordinary course,” the judge added.
The dispute concerns Sony‘s proposed Second Amended Complaint and the papers filed in support of it.
Sony Music filed its motion for leave to amend on May 22, seeking to add more than 30,000 recordings to the case.
In the proposed complaint, the labels allege that Udio “copied and ingested” 30,442 of their copyrighted works into the company’s generative AI models, as MBW reported last month.
Sony says it identified those additional works in discovery after gaining access to Udio‘s training data.
Document production in the case is currently scheduled to close on June 26, 2026.
At the heart of the dispute is a single figure: the size of Udio‘s training dataset.
In a memorandum filed on June 1, which you can read here, Udio said it wants to seal references to the volume of audio files that Sony claims it used to train its generative AI models, a figure its lawyers call the “Training Data Number.”
Udio argued that if competitors learned the figure, they could “develop and refine competing products more rapidly and at a lower cost.”
The company said it is not seeking to seal any specific recording, telling the court that “the sole information Udio seeks to impound is the total number of audio files allegedly used to train its model.”
The request follows Suno, which made the same move in the labels’ separate copyright case against it in Massachusetts.
Udio said it intends to oppose Sony‘s motion to amend.
Udio, which is operated by Uncharted Labs, sought to seal only a handful of references to that figure, in Sony‘s memorandum of law, the proposed complaint, a redline of it, and a declaration from Daniel Delorey.
Sony, joined by co-plaintiffs Arista Music and Arista Records, filed redacted versions of the documents on the public docket.
Sony‘s notice, which you can read here, said the material contained information that Udio “has indicated it believes to be sensitive confidential information that should be sealed from the public record.”
Sony said it filed the material under seal to give Udio “an opportunity to file with the Court a statement of the reasons that such material shall be filed under seal.”
Under the protective order governing the case, the party seeking to keep material sealed must file its reasons within five business days of a motion to seal.
The plaintiffs added that they “expressly reserve the right to object to Udio‘s sealing some or all of the designated material.”
Sony is represented by law firm Hueston Hennigan; Udio is represented by Latham & Watkins.
All three major record companies – Sony, Universal Music Group and Warner Music Group – sued Udio and rival platform Suno in June 2024, accusing both of “mass infringement” of copyright.
UMG settled its claims against Udio in October 2025, and Warner followed in November 2025, leaving Sony as the sole remaining major-label plaintiff in the case.
As part of those settlements, UMG and Warner struck licensing deals with Udio for a licensed AI music platform due to launch in 2026.
In its April answer, Udio admitted that it “obtained audio data from YouTube for use as training data,” while maintaining that its use of copyrighted music amounts to “fair use.”
Udio also acknowledged using a tool called YT-DLP to acquire some of that training data.
Both sides are heading toward motions for summary judgment focused on the fair use question, according to Sony‘s motion.Music Business Worldwide
