Cox v Sony: Infringers gonna infringe – unless service providers encourage them

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Cox v Sony: Infringers gonna infringe – unless service providers encourage them

 Söğüt Atilla-Aydın Monday, April 13, 2026 - contributory infringement, copyright, Cox v Sony, internet service providers, safe harbour, Söğüt Atilla-Aydın

On 25 March, the US Supreme Court ruled that Cox Communications, Inc. is not contributorily liable for its users’ acts of copyright infringement against Sony Music Entertainment. Although two judges diverged from the majority in their reasoning, all agreed that Cox does not induce, encourage, or intend to aid its users’ infringing activities.

Background

Cox is an Internet service provider (ISP), serving approximately 6 million subscribers, each account being associated with a unique Internet Protocol (IP) address. These accounts are not necessarily tied to specific individuals. They do include subscriptions that allow an indeterminate number of individuals to access the Internet, such as households, coffee shops, or college dormitories. As a result, Cox – just like other similarly situated ISPs – is said to be unable to identify who is using their services or for what purpose, nor can it directly supervise or control users’ online activities. 

Sony, a music copyright owner, has been struggling to enforce its rights given the prevalence and ease of online infringement. Against this backdrop, Sony attempted to enforce its copyrights not against individual infringers, but against ISPs, such as Cox. To this end, Sony relied on a monitoring software called ‘MarkMonitor’ – which detects uploads and downloads of infringing material and traces those acts to specific IP addresses and, consequently, to the relevant ISP. Once identified, MarkMonitor sends infringement notices to the relevant ISP, requesting appropriate action.

Over a two-year period, Cox received more than 160,000 such notices and claimed to have implemented a graduated response system: it initially sends a warning to the relevant subscriber; if infringement continues, it temporarily terminates Internet access until the subscriber responds; and, as a final step, it suspends service. Cox further emphasised that its subscriber agreements explicitly prohibit posting, copying, transmitting, or disseminating infringing content. According to Cox, these measures resulted in the termination of approximately 98% of the reported infringements.

Sony, nevertheless, considered these efforts inadequate, pointing out that Cox had terminated only 32 subscribers for copyright infringement. Therefore, Sony argued that Cox was both contributorily liable – as it continued to provide Internet access despite knowing that certain subscribers were associated with infringing activities – and vicariously liable – as it allegedly profited directly from the infringements and possessed the right and ability to supervise the users.

The District Court sided with Sony on both grounds while, on appeal, the Fourth Circuit rejected the vicarious liability claim, finding that Cox did not receive a direct benefit from the infringements. However, it affirmed contributory liability, reasoning that Cox continued to provide Internet access to known infringers.

The Supreme Court’s decision

Relying on its own precedent in Grokster and Sony, the Supreme Court emphasised that service providers are contributorily liable for users’ infringements only where they intend their services to be used for infringement. In other words, they can be contributorily liable only when the copyright owners can demonstrate that the ISPs induced – i.e., actively encouraged – infringement through specific acts or tailored their services in a way that leaves no room for substantial or commercially significant non-infringing uses.

Viewed against this legal standard, Cox’s conduct fell short of contributory infringement. Far from encouraging infringement, Cox took steps to deter it, by warning users and suspending or terminating access. Moreover, Cox’s services are clearly capable of non-infringing use: Internet access facilitates countless lawful activities and is not, in itself, a vehicle for piracy. The Court, therefore, rejected the contributory infringement claims. Holding otherwise – by treating the mere possibility of unlawful use as sufficient – would have unjustifiably expanded the scope of copyright liability and imposed unreasonable obligations on service providers.

Having rejected contributory liability, the Court then addressed the Fourth Circuit’s reasoning that ‘supplying a product with knowledge that the recipient will use it to infringe copyrights is exactly the sort of culpable conduct sufficient for contributory infringement’. The Supreme Court confined contributory infringement to (i) inducing infringement and (ii) tailoring one’s services specifically for the relevant infringement; and thus, made clear that mere knowledge of infringement, or a failure to take additional preventive measures, exceeds what its case law has established.

Comment

A Kat overwhelmed by the Supreme Court's decision – her paws, unfortunately, tied...

Equating ISPs’ mere knowledge or awareness of ongoing infringement with contributory liability is challenging. As this Kat has previously argued, platforms and service providers should only be held accountable for failing to take the actions that can reasonably be expected from them. Liability should arise, for instance, where a provider neglects to address a specific instance of reported infringement. Otherwise, the purpose of “safe-harbour” protections would be undermined. Moreover, such an aggressive approach to service provider liability could impair the functioning of Internet services. Had the Supreme Court required Cox to ensure that each individual user – including those sharing a single account – engaged exclusively in lawful activity, Cox would have been forced to implement intrusive and costly monitoring technologies, effectively requiring policing users’ online conduct. Such overly broad precautions sound neither proportionate nor fair, particularly given that Cox’s existing ‘warning and suspension’ system reportedly resolved 98% of the identified infringements.

One aspect of the Supreme Court’s reasoning that invites criticism is its strict limitation of secondary liability to the categories previously identified in Grokster and Sony. This concern was raised by Justices Sotomayor and Jackson in their concurring opinions. They, in essence, suggested that fault-based liability principles derived from common law – most notably, aiding and abetting – might justify recognising an additional form of secondary liability. On this view, if Sony could demonstrate that Cox had helped users succeed in their copyright infringements, liability might have arisen even absent inducement or tailored service design.

Even then, however, merely supplying Internet access, cannot reasonably be characterised as aiding a specific instance of infringement. Importantly, the concurring judges also underlined that Cox’s lack of knowledge of the individuals who actually infringed Sony’s copyrights was ‘fatal’ for the secondary liability claim, as Cox was only notified of the IP addresses, not of specific users. 

This Kat accepts that the outcome – reached through different rationales – is far from desirable for copyright owners, such as Sony, who are implicitly asked to tolerate a degree of ongoing online copyright infringement. The solution, however, does not lie in imposing unreasonable, and perhaps even practically impossible, duties on service providers, nor in requiring them to oversee every activity online. Striking a fair balance between copyright owners and ISPs cannot mean placing the entire burden on the latter. Where copyright owners can identify only IP addresses linked to accounts, rather than the individuals responsible for infringement, it is only reasonable for service providers to suspend or terminate those accounts. Requiring further punitive or preventive measures would skew the balance significantly in favour of copyright owners, allowing them to reap the benefits of copyright enforcement without first bearing the investigative burden of identifying infringers.

Photo credit: Lauren Crais

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