How Low Can You Go? Courts Lower Marking Defense Burden, Raising Patent Damages Risks

1. Courts Are Making It Easier for Accused Infringers to Pursue Patent-Marking Defenses: Recent decisions in SK Nexilis v. Solus Advanced Materials and DivX v. Netflix held that, with the right facts, identifying potentially unmarked products—without linking them to specific asserted patents—can satisfy the accused infringer’s initial burden under Arctic Cat. So, the threshold of proof required for the accused infringer to shift the burden onto the patent owner to prove compliance with the marking statute is low.
   
   
2. Patent Owners Face Great Risk of Losing Pre-Suit Damages Without Proper Marking Provisions: Once an accused infringer identifies allegedly unmarked products, the burden shifts to the patentee to prove those products were properly marked or did not require marking. Courts continue to place the ultimate responsibility for demonstrating compliance squarely on the patent owner. This reinforces the importance of marking provisions in licenses, if the licensed product practices a patent.
   
   
3. Patent Owners Placed on Notice of a Marking Defense Must Defend Against It: The accused infringer’s burden under Arctic Cat to identify products that should have been marked is one of notice. As SK Nexilis and DivX demonstrate, Courts will account for litigation conduct when deciding whether the notice burden is met. Then, the patent owner must demonstrate compliance instead of resting on the accused infringer’s alleged failure to meet its initial burden.

Texas and California federal district courts in 2025 and 2026 have lowered the bar for identification of unmarked articles under Arctic Cat v. Bombardier Recreational Products. What are the commercial implications of this development for companies that use patents to make money, protect their products and achieve business goals? Marking provisions in patent licenses are key for repeat patent plaintiffs because marking defenses may not be easily defeated on technicalities.

As the U.S. Court of Appeals for the Federal Circuit explained in the 2017 precedential ruling, an accused infringer bears the initial burden, which is expressly a “low bar”, to identify products that a patentee should have marked under the marking statute. In recent cases, courts applying Arctic Cat have found that listings of products untethered to an asserted patent satisfy this burden.

A review of the facts of these cases, however, demonstrates how these listings placed the patentee on notice of the accused infringer’s allegations under the marking statute.

Arctic Cat Sets a “Low Bar” For a Marking Defense 

Under 35 USC § 287, a U.S. patent owner (including any licensees) with a product embodying its patent may recover pre-suit damages for infringement only after providing notice to the accused infringer of the asserted patent rights. Two types of notice are recognized by statute:

1. actual notice, satisfied after the patentee informs the infringer of the alleged infringement; and
2. constructive notice, accomplished by affirmatively marking patented articles according to the statute.

An accused infringer can invoke Section 287’s bar to pre-suit damages where the patentee failed to mark its practicing products. To do so, the accused infringer bears an initial burden of production to identify alleged unmarked “patented articles”. Then, the burden shifts to the patentee to prove that the identified articles either (1) are marked in accordance with Section 287; or (2) did not need to be marked, for instance because the products do not practice the patent or are unlicensed.

In Arctic Cat, the Federal Circuit described the infringer’s initial burden of production as a “low bar”. Indeed, the infringer does not need to prove these identified articles practice the patented invention. Rather, the accused infringer must simply put the patentee on notice of specific unmarked products that the accused infringer believes may practice the asserted patent.

But how low is the “low bar”? Recent Texas and California cases provide guidance.

How “Low” Can An Accused Infringer Go to Satisfy Its Production Burden? 

In SK Nexilis v. Solus Advanced Materials, a case issued 6 April 2026 by the U.S. District Court for the Eastern District of Texas involving multiple asserted patents, U.S. Magistrate Judge Roy Payne found that the accused infringer’s initial burden of production “is only to identify which products practice the asserted patents, not which patents those products practice”.

There, patentee SKN identified its own product as practicing one of its five asserted patents. In response to an interrogatory, accused infringer Volta identified the same product as practicing “one or more” of the patents. Then, after conceding that the identified product practices two of its asserted patents, not just one, SKN argued that Volta’s “one or more” language failed to satisfy Arctic Cat’s initial burden of production because it did not identify any product as practicing any particular asserted patent.

Judge Payne was unconvinced. He found that Volta identified the SKN product that should have been marked, and that Arctic Cat did not require SKN to match alleged unmarked articles to specific asserted patents. Arctic Cat’s initial burden of production is one of notice, and Judge Payne found that SKN did not need additional notice about its own products that it had identified in its own disclosures.

Judge Payne’s ruling reinforces the Federal Circuit’s guidance in Arctic Cat: the patentee bears the burden of pleading and proving compliance with the marking requirement because whether the patentee’s products have been marked “is a matter peculiarly within its own knowledge” (as stated in Dunlap v. Schofield, U.S. Supreme Court, 1894).

Similarly, in DivX v. Netflix, a case issued 18 December 2025 by the Central District of California, accused infringer Netflix identified products it contended should have been marked via a letter to DivX. Netflix did not tie the identified products to any specific asserted patent, and DivX argued the letter failed to meet the initial Arctic Cat burden to identify product believed to be unmarked “patented articles”.

The court disagreed, finding that Netflix’s letter satisfied its burden because specifically identifying the unmarked products necessarily implied that Netflix believed these products practice the asserted patents. Indeed, the court noted that in opposing a motion for summary judgment of no pre-suit damages, DivX presented evidence that it required licensees of a disputed patent to mark their products and that it audited its licensees’ marking compliance.

Exercise Caution 

Under SK Nexilis and DivX, an accused infringer looking to satisfy its Arctic Cat burden would be well served to be mindful of how the patentee would reasonably receive “notice” of identified unmarked products. As these cases illustrate, the record may support a broad listing of products without a specific tie to any one asserted patent, especially if the patentee previously identified the products or can infer that the identified products are believed to practice a particular asserted patent.

Because of SKN’s identification of its own products and DivX’s licensee marking obligations, however, accused infringers should exercise caution before reading SK Nexilis and DivX beyond their facts. Meanwhile, patentees should remember Arctic Cat’s refrain that the ultimate burden to demonstrate compliance with the marking statute remains squarely on the patentee.

A patentee attempts to sidestep this burden with innuendo and technicalities at its own risk.