But I’m an Inventor! HIP v. Hormel Foods Demonstrates that a Significant Contribution Is Required to Be a Co-Inventor on a Patent

On May 2, 2023, the U.S. Court of Appeals for the Federal Circuit issued a precedential opinion in HIP, Inc. v. Hormel Foods Corp. that reversed a district court’s decision to grant plaintiff’s request to have their employee listed as an inventor, finding that HIP employee David Howard’s alleged contribution to U.S. Patent No. 9,980,498 was “insignificant in quality” when “measured against the dimension of the full invention.”1 The patent is directed to “methods of precooking bacon and meat pieces,” and claims “a two-step method that involves a first preheating step using a microwave oven, infrared oven, or hot air, and a second, higher-temperature cooking step.”2 The Federal Circuit Panel determined that Howard’s contribution of preheating meat pieces using an infrared oven was “insignificant” in view of the specification as a whole. Therefore, the Panel reversed the lower court and ultimately held that Howard was not an inventor.3


Hormel owns the patent directed to methods of precooking bacon and meat pieces. After years of extensive testing, including enlisting HIP and its employee, Howard, in an effort to improve the methods used for precooking meat, Hormel finally settled on a two-step cooking process and filed a patent application claiming this process, listing four individuals as inventors.  Notably, Hormel left HIP’s Howard out of the list of inventors.4 The application issued as the patent-in-suit, and all of the named inventors assigned their rights to Hormel.5

Believing that Howard should have been listed as an inventor because of his contributions to the patented invention, HIP sued Hormel in the United States District Court for the District of Delaware.6 After a bench trial, the district court determined that while Howard was not the sole inventor, he was a joint inventor based solely on his contribution of the use of infrared preheating, which is one of the claimed preheating options.7 The court found that the infrared preheating concept was significant, Howard’s testimony was corroborated by another employee’s testimony, and that testimony from the Hormel inventors revealed that they did not conceive of preheating with an infrared oven.8 Thus, the court ordered that Howard be listed as a joint inventor on the patent.9 Hormel appealed.

On appeal, Hormel raised two issues: (1) that Howard was not a joint inventor “because the alleged contribution of preheating with an infrared oven was well known and part of the state of the art and because it was not significant when measured against the scope of the full invention,” and (2) that Howard’s testimony was insufficiently corroborated to satisfy his burden to prove that he should have been added as an inventor.10


Inventorship is a question of law.11  “The burden of proving that an individual should have been added as an inventor to an issued patent is a ‘heavy one,’”12 and “the issuance of a patent creates a presumption that the named inventors are the true and only inventors.”13 An alleged joint inventor must prove their claim to be added as an inventor by clear and convincing evidence.14

“To qualify as a joint inventor, a person must make a significant contribution to the invention as claimed.”15  One must successfully argue that all elements of the three-part Pannu test are met.16 It must be shown that the individual: “(1) contributed in some significant manner to the conception of the invention; (2) made a contribution to the claimed invention that is not insignificant in quality, when that contribution is measured against the dimension of the full invention; and (3) did more than merely explain to the real inventors well-known concepts and/or the current state of the art.”17


Hormel made multiple arguments as to why Howard was not a joint inventor. In particular, Hormel argued that the “district court failed to analyze the significance of the alleged contribution in light of the full invention (the second Pannu factor) and also erred in its conclusion that the infrared preheating language in claim 5 was significant (the first Pannu factor).”18 In its argument, Hormel relied on the fact that infrared heating is rarely mentioned across the specification, claims, and figures.19 The specification mentions infrared ovens only once, while microwave ovens are consistently mentioned throughout the specification.20 Hormel argued that “the mere inclusion of the infrared oven language in a claim is not sufficient to label that contribution significant.”21  In reply, HIP argued that the district court did not err in determining that Howard’s preheating contribution was not insignificant in view of the whole invention.22

Ultimately, the Panel concluded that Howard was not a joint inventor.23 While HIP and Hormel raised other arguments, the Panel’s analysis focused on the second Pannu factor because “the failure to meet any one factor is dispositive on the question of inventorship.”24  The second Pannu factor considers whether the inventor “ma[de] a contribution to the claimed invention that is not insignificant in quality, when that contribution is measured against the dimension of the full invention.”25 The Panel considered Howard’s contribution of preheating meat pieces using an infrared oven to be insignificant in quality.26 First, it was mentioned only once in the patent specification.27 Second, the alleged contribution was recited only in a single claim (and that mention occurred in a group alongside a microwave oven and hot air).28

The Panel contrasted the disclosure of infrared oven preheating with the disclosure of microwave oven preheating.29  According to the Panel, the difference in significance between infrared and microwave preheating was clear.  As the Panel explained, “[p]reheating with microwave ovens, and microwave ovens themselves, feature prominently throughout the specification, claims, and figures.”30 Further, the Panel noted that microwave ovens were even mentioned in the brief summary of the invention, in contrast to the lack of any mention of infrared ovens in the summary.31 That there was no mention of preheating with an infrared oven in the examples and the figures “further emphasize the centrality of the microwave oven.”32  Thus, the Panel reversed the district court, holding that Howard is not a joint inventor of the patent because his contribution to the claims was insignificiant.33


The Panel’s opinion demonstrates that the question of whether an individual is an inventor of a patent requires a fact-intensive inquiry with the Pannu factors framing the analysis. This opinion illustrates that to be an inventor on a patent it is important to contribute something to the patented invention that is “significant in quality” that rises above more than merely explaining well-known concepts and/or the state of the art. While proving that an individual should have been added as an inventor is a difficult hurdle to overcome, it can be achieved given the facts of a particular circumstance.

1 HIP, Inc. v. Hormel Foods Corp., 66 F.4th 1346, 1353 (Fed. Cir. 2023) (quoting Pannu v. Iolab Corp., 155 F.3d 1344, 1351 (Fed. Cir. 1998)).
2 Id. at 1347.
3 Id. at 1346.
4 Id. at 1349.
5 Id.
6 Id.
7 Id.
8 Id.
9 Id. at 1350.
10 Id.
11 Id. (quoting Gen. Elec. Co. v. Wilkins, 750 F.3d 1324, 1329 (Fed. Cir. 2014)).
12 Id. (citing Pannu, 155 F.3d at 1349 (quotation omitted)).  
13 Id. (quoting Gen. Elec., 750 F.3d at 1329).
14 Id. (quoting Hess v. Advanced Cardiovascular Sys., Inc., 106 F.3d 976, 980 (Fed. Cir. 1997)).
15 Id. (citing Fina Oil & Chem. Co. v. Ewen, 123 F.3d 1466, 1473 (Fed. Cir. 1997)).
16 Id. (citing Pannu, 155 F.3d at 1351).
17 Id.
18 Id. at 1351.
19 Id.
20 Id.
21 Id.
22 Id.
23 Id. at 1351.
24 Id. at 1353.
25 Id. (quoting Pannu, 155 F.3d at 1351).
26 Id. at 1352.
27 Id.
28 Id.
29 Id.
30 Id.
31 Id.
32 Id.
33 Id. at 1353.