On March 25, 2026, the U.S. Supreme Court issued a 9-0 unanimous ruling in favor of Cox Communications in the case brought by Sony Music Entertainment seeking to hold Cox liable for copyright infringements committed by its Internet service customers.  The Supreme Court used this decision as an opportunity to rewrite the rules for when a third-party is liable for such “contributory infringement” of copyright. 

For decades, the standard for such claims was clearly understood to consist of “knowledge, plus material contribution.”  The Supreme Court has now abandoned that standard, restricting the liability to affirmatively inducing third parties to infringe, or providing services specifically designed for infringement.

In this case, the music company plaintiffs including Sony sued Cox for both contributory and vicarious copyright infringement of over 10,000 copyrighted works.  A Virginia federal jury found Cox liable under both legal theories, and the Fourth Circuit Court of Appeal agreed there was contributory liability.  However, the appeal court reversed the jury’s finding of vicarious liability, ordering the district court to recalculate the jury’s $1 billion damages award.

Instead, Cox appealed to the Supreme Court, where Justice Thomas wrote the court’s opinion, with Justice Sotomayor writing a separate opinion concurring in the result, but criticizing the majority opinion for unnecessarily narrowing the doctrine of secondary copyright liability.

Despite the existence of starkly worded emails in which Cox employees seemed not to care whether Cox’s internet service customers were infringing copyrights, and a paltry number of enforcement efforts by Cox, the Supreme Court found the evidence was not enough to support holding Cox liable for not terminating those customers’ internet service.  Instead, the new standard is that only someone “intending its service to be used for infringement” will be liable for contributory infringement.  Over the criticism from Justice Sotomayor (and Justice Ketanji Brown Jackson, who concurred with her opinion), Justice Thomas held that an entity will only be found to have intended its service to be used for infringement if it either affirmatively induced others to infringe (citing the Supreme Court’s 2005 ruling in MGM v. Grokster) or if it offers services that are specifically “tailored to infringement.”  Furthermore, the court held that a service is only “tailored to infringement” if it is not capable of “substantial” or “commercially significant” non-infringing uses (citing the Supreme Court’s 1984 ruling in Sony Corp. of America v. Universal City Studios).

In this way, the Supreme Court overruled the long-standing broader definition of contributory infringement from the Second Circuit’s 1971 decision in Gershwin Publishing Corp. v. Columbia Artists Management.  In overruling that case, the Supreme Court has rendered irrelevant much of the carefully-negotiated safe harbors for Internet service providers enacted by Congress in the Digital Millennium Copyright Act, section 512.  The Court’s opinion is also a boon to the many AI companies currently being accused of providing copyrighted infringing output at the behest of their users.  Those AI companies and any other distributors of infringing content created by other others can now point to whatever non-substantial non-infringing uses their services provide, thereby escaping liability under the theory of contributory infringement.

So far, courts have not restricted the scope of liability for vicarious infringement, however, which attaches to those who directly profit from others’ infringement despite having the right and ability to control that infringement.  The owners of companies distributing infringing or counterfeit goods or services are the clearest example of those who will continue to be liable under that theory for the infringements of others, as Cox Communications was here.  But AI companies and anyone else who previously would have been concerned that they were supplying services that materially contributed, even indirectly, to the distribution of infringing content, can take great comfort from the Supreme Court’s recent decision on contributory infringement.