We're back! And we have a stack of opinions to look through. The first one that caught my eye is a summary judgment opinion from visiting Judge Murphy of the Eastern District of PA, in Monolithic Power Systems, Inc. v. Reed Semiconductor Corp., C.A. No. 23-1155 (D. Del.).
The Court addressed various summary judgment motions and Daubert motions by both sides, and denied them all. One denial in particular is worth discussing.
The accused infringer moved for summary judgment on pre-suit damages because the patentee failed to mark its products that embody the patent. According to the opinion, the accused infringer sent an interrogatory to the patentee asking it to identify products covered by the asserted patents. The patentee responded by stating that certain products "embody" those patents:
During discovery, [accused infringer] Reed propounded an interrogatory seeking identification of “all MPS Covered Products,” the definition of which was not provided to us. Appx. 720 (Reed did not include the definitions page of the interrogatory in the appendix). In response, [patentee] Monolithic identified certain products that “embody the ’608 patent” and “embody the ’377 patent” without explaining what “embody” means and without, apparently, adopting whatever the definition of “MPS Covered Products” may have been. Appx. 721, 724-26, 770.
Monolithic Power Systems, Inc. v. Reed Semiconductor Corp., C.A. No. 23-1155, at 8 (D. Del. Apr. 13, 2026). The patentee admitted it did not mark its products. Id.
In its motion, the accused infringer alleged that since the patentee had admitted the products embody the asserted patents, and the products are not marked, the burden shifts to the patentee to show marking. Id.
The Court disagreed:
On this record, Reed argues that Monolithic failed to carry its burden of proving compliance with the marking requirement under Arctic Cat Inc. v. Bombardier Recreational Prods. Inc., 876 F.3d 1350, 1369 (Fed. Cir. 2017). We disagree because Arctic Cat requires Reed to make the first move: the defendant has the “burden of production to identify unmarked products that it alleges should have been marked.” Id. Reed starts out down this road (“once Defendants identify unmarked products”) but then incorrectly flips the burden to Monolithic (“MPS Practicing Products that MPS identified as embodying the Asserted Patents”). DI 357 at 18 (internal quotations omitted and emphasis added); see also DI 335 at 28 (“MPS has identified 11 MPS Practicing Products, which MPS contends practice the Asserted Patents.”). As far as we can tell, Reed never actually took the position that certain Monolithic products should have been marked, as required by Arctic Cat. It might be possible to force the patent owner to make the first move using an interrogatory, but that did not happen here because Reed relies upon unstated definitions and shifting uses of the general terms “cover,” “embody,” or “practice.” On this record, Monolithic’s argument is entirely understandable: the relevant Monolithic products embody aspects of the patents, but neither side has actually taken the position that one or more claims reads on one of those products (and therefore should have been marked). And without that, the Arctic Cat burden-shifting process does not even get started.
The Court also implies that the accused infringer tried to shift the burden to the patentee in its concise statement of facts:
[A]t the motions stage, in the first proposed undisputed fact, Reed lists several Monolithic products and asserts that Monolithic “has identified the following products as practicing” the patents. . . . That seems a bit presumptuous given the interrogatory record, and indeed Reed responded that the interrogatory responses spoke for themselves and that Reed did not “demonstrate a limitation-by-limitation comparison of any claim of either” patent. Id.
Overall, the Court's basic point seems to be that if the accused infringer wanted to make a marking argument, it needed to (1) identify the specific products that were unmarked and (2) argue that those unmarked products met specific claims of the asserted patents. The accused infringer seems to have failed primarily at step two, because it did not argue that any product met any particular claim in a way that would shift the burden to the patentee to show that it didn't.
In any event, this is a good reminder of how important it is to review the Arctic Cat burden-shifting analysis if you have a case that involves an alleged failure to mark. It seems straightforward, but the burden-shifting framework can really trip people up.
If you enjoyed this post, consider subscribing to receive free e-mail updates about new posts.
