Universal and Sony Are Suing Suno Again, and This Time They Want the New Model Too

TL;DR: Universal Music Group and Sony Music filed a second copyright lawsuit against AI music platform Suno on September 18, alleging its new v6 model infringes 60,202 sound recordings. The labels argue v6 isn’t a clean break from the earlier, allegedly stolen training data, calling it “the fruit of the same poisoned tree.” Warner Music, BMG, and Believe have already settled and licensed their catalogs to Suno, leaving Universal and Sony as the last major holdouts still fighting in court.

“The fruit of the same poisoned tree.” That’s the actual language Universal Music Group and Sony Music used in a new federal complaint filed against Suno on September 18, and it tells you exactly where this is headed.

The two majors filed suit in Massachusetts, alleging Suno’s newly launched v6 model infringes 60,202 sound recordings, a number they say represents just a slice of the real total. It’s the second lawsuit these labels have brought against the AI music startup, and unlike the first one, this one is squarely about whether Suno can outrun its own legal history by releasing a new model.

How you launder a training set

Suno’s defense so far has leaned on knowledge distillation, a technique where a new “student” model learns from both fresh data and the outputs of older “teacher” models. The problem, according to the lawsuit, is that those teacher models were trained on recordings the labels say were scraped and stream-ripped without permission in the first place. Train a new model on an old model’s outputs, and whatever was baked into the old model doesn’t just disappear.

UMG and Sony aren’t buying the fresh-start argument. Their complaint calls v6 “not a fresh start” but rather a continuation of the same underlying infringement, dressed up in a new release. It’s a clever legal framing, since it sidesteps having to prove infringement in the new model from scratch and instead argues the taint carries forward.

Suno has also leaned hard on a fair use defense, the same one OpenAI, Meta, and other AI companies have used to justify training on copyrighted material. The labels reject that framing outright. Their complaint draws a sharp line: fair use exists to protect human expression, they argue, and Suno offers “imitative machine-generated music,” not human creativity or expression. That’s a direct shot at the idea that an AI model deserves the same legal latitude a human artist gets when sampling or drawing inspiration from existing work.

Why some labels settled and these two didn’t

Here’s what makes this case interesting rather than just another AI lawsuit: Warner Music, BMG, and Believe already reached licensing deals with Suno. Suno actually built v6 in partnership with those three labels, which means the company has proof that a negotiated path exists. Universal and Sony are choosing litigation instead, which suggests either they think they can extract a better deal by fighting first, or they genuinely want Suno’s practices changed rather than just monetized.

That split puts real pressure on Suno’s business model. Half its major-label relationships are commercial partnerships. The other half is an active courtroom fight demanding damages and potentially an injunction. Running both tracks simultaneously is not a comfortable position for a company that needs licensed content to keep growing.

What happens next is genuinely unclear. The plaintiffs haven’t said publicly whether a settlement would satisfy them or whether they’re after something closer to shutting down Suno’s current approach entirely. Courts have already rejected attempts to fold new tracks into the existing case, which is part of why this arrived as a standalone lawsuit rather than an amendment.

Bottom Line: This case matters beyond music. If “poisoned tree” reasoning holds up in court, it becomes a template for going after every AI company that trains new models on outputs from older, legally contested ones, a practice that’s more common across the industry than most companies would like to admit.