Cox Communications, Inc. v. Sony Music Entertainment

Cox Communications v. Sony Music Entertainment, decided March 25th, 2026. The Supreme Court, in an opinion by Justice Thomas, reversed the Fourth Circuit and held that an Internet service provider is not contributorily liable for its subscribers' copyright infringement merely because it kept serving accounts it knew were being used to infringe. Seven Justices joined the opinion; Justice Sotomayor, joined by Justice Jackson, concurred only in the judgment. Here's the brief.

Cox is an Internet service provider with about six million subscribers. Each account maps to a single IP address, which many people may share — a household, a coffee shop, a dorm. Cox knows which account owns an address, but it cannot tell which person is behind any given use.

Sony Music Entertainment and other major music labels have struggled to police infringement in the age of online sharing. Rather than sue individual infringers, they enlisted a company called MarkMonitor to detect infringing activity and trace it to IP addresses. Over roughly two years, MarkMonitor sent Cox 163,148 notices identifying subscriber addresses tied to infringement.

Cox ran a graduated response — warnings, then suspensions, then, after thirteen notices, termination — though Sony pointed out that Cox terminated only thirty-two subscribers for infringement in that period. Sony sued in the Eastern District of Virginia on two theories: contributory and vicarious liability. The jury found for Sony on both, found the infringement willful, and awarded one billion dollars in statutory damages. The Fourth Circuit affirmed contributory liability but reversed on vicarious. The Court granted cert only on contributory liability.

The question: is an ISP contributorily liable for a user's infringement simply because it keeps providing service knowing the service is being used to infringe?

The Copyright Act makes anyone who violates a copyright owner's exclusive rights an infringer, but it does not expressly make anyone liable for another's infringement. The Court's precedents recognize two judge-made categories of secondary liability: contributory and vicarious. Only contributory liability was before the Court.

Contributory liability, the Court explained, requires that the provider intended its service to be used for infringement — and that intent can be shown in only two ways: the provider actively induced the infringement, as in Grokster, or it supplied a service tailored to infringement, one not capable of substantial noninfringing uses, as in the Betamax case, Sony. The Court noted these two bases track patent law.

Applying that framework, the Court held Cox liable under neither path.

On inducement: Cox never encouraged its subscribers to infringe. There was no evidence of promotion or marketing of infringement; to the contrary, Cox repeatedly discouraged it — sending warnings, suspending service, and terminating accounts. On tailoring: Internet access is plainly capable of substantial noninfringing uses. Cox simply supplied a connection used for countless lawful purposes.

That left Sony's core theory — that knowingly serving infringers is itself enough. The Court rejected it.

The Fourth Circuit had held that supplying a product knowing the recipient will use it to infringe is sufficient for contributory infringement. That, the Court said, invented a third basis for liability its precedents do not recognize.

The Court also turned aside Sony's argument that the DMCA safe harbor presupposes ISP liability. The safe harbor, the Court explained, creates defenses; it does not itself impose liability.

Justice Sotomayor, joined by Justice Jackson, concurred in the judgment. She agreed Cox was not liable, but faulted the majority for treating inducement and tailoring as the only routes to contributory liability — arguing Grokster left the door open to common-law theories like aiding and abetting, on which Sony's proof of intent also failed.

Cox confirms that contributory copyright liability turns on intent, not knowledge. A provider must have intended its service to be used to infringe — shown by active inducement or by a service good for nothing but infringing — and mere awareness that some customers will misuse an otherwise lawful service is not enough. The Court anchored both bases in the same doctrine that governs patent inducement and contributory infringement under sections 271(b) and (c), reaffirming the historic kinship between copyright and patent secondary liability that runs through Sony and Grokster.

Cox Communications, Inc. v. Sony Music Entertainment, 607 U.S. ___, decided March 25th, 2026. I'm Kyle Coleman. Thanks for watching.