Billboard reports that Universal Music Group and Sony Music's landmark lawsuit against AI music platform Suno — now nearly two years into a discovery process running through mid-2027 — has spawned a wave of third-party subpoenas, and a slew of filings around the October 14 deadline show several major companies fighting them.

According to Billboard, Apple Music complied with six document subpoenas from both sides, including 'granular' data on Suno-generated music on its platform and how it detects and tags AI tracks, but is asking a judge to block a Suno deposition subpoena it calls 'overbroad.'

Meanwhile, Billboard says Suno filed its own petition against the Mechanical Licensing Collective, and the labels have clashed with DIY distributor DistroKid, which claims the requested AI-track data 'has no bearing' on the central AI-training issue.

What makes this round unusual is that the resistance comes from entities on both sides of the fight, not just from the AI defendant's allies.

Digital Music News observes that a 'subpoena maelstrom' has taken hold, with at least seven Series D investors facing demands, and notes that even Apple — a party-friendly streamer that had already handed over extensive documents — moved to quash a demand from Suno while Suno itself targeted the MLC with a motion to compel.

Digital Music News also highlights that Bond Capital, which led Suno's $400 million Series D in June, points out the majors' cases predate its investment by roughly two years, complicating the labels' theory that its diligence papers show Suno's state of mind.

The breadth of the fights, both outlets suggest, shows discovery has spilled far beyond the named parties.

According to Billboard, UMG and Sony want DistroKid — the industry's largest DIY distributor — to supply a monthly tally of AI-generated tracks and their streams and royalties, arguing the metrics will prove machine-generated music competes with human works; DistroKid has refused, saying it will 'continue to cooperate with the legal process' while disputing relevance, and UMG is separately suing it over 'AI-generated slop.'

Billboard also reports the labels won permission Monday (Oct. 26) to depose former Menlo Ventures principal C.C.

Gong, whose post that he had 'personally shifted most of my listening to Suno' they call key evidence of market substitution. Digital Music News adds that the labels seek Bond's draft investment memoranda, due-diligence materials and internal projections about Suno's market impact.

The stakes are enormous because, as Billboard explains, a judge will eventually decide whether it was 'fair use' for Suno to train its service on millions of unlicensed UMG and Sony tracks — Warner settled and licensed last year.

Digital Music News emphasizes that the fourth fair-use factor, the effect on the market for the protected works, is where these subpoenas could matter most: play-volume data from the MLC and streamers could help either side score a 'precedent-setting win' whose effects could reverberate across the wider copyright landscape.

Billboard notes discovery continues through mid-2027, and with Suno also facing suits from Reservoir, Round Hill and others per Digital Music News, the subpoena battles — and the motions to quash — look set to keep expanding.