Steuben Foods, Inc. v. Shibuya Hoppmann Corp., 127 F.4th 348 (Fed. Cir. 2025)
In a recent decision, the Federal Circuit in Steuben Foods, Inc. v. Shibuya Hoppmann Corp. left the application of the reverse doctrine of equivalents hanging on by a thread. While the CAFC found Steuben’s RDOE arguments compelling, it ultimately held that resolving the RDOE issue was not necessary to determine that the district court’s judgment as a matter of law (JMOL) of noninfringement was improper.
What is the reverse doctrine of equivalents?
The reverse doctrine of equivalents (RDOE), as its name alludes to, operates as an inverse to the doctrine of equivalents. Prior to the passing of the Patent Act of 1952, the Supreme Court laid out the reverse doctrine of equivalents in Graver Tank & Mfg. Co., Inc. v. Linde Air Products Co., 339 U.S. 605 (1950). There, the Court held that an alleged infringer could defeat a judgment of infringement by showing that while their accused product might perform the same or similar function as the asserted claim, it is “so far changed in principle” from the asserted claim that it performs that function in a substantially different way.
When a patent owner alleges infringement, they bear the initial burden of proving infringement. Under RDOE, the burden then shifts to the alleged infringer to establish a prima facie case of noninfringement under RDOE. Once the alleged infringer has done so, the burden shifts back to the patentee to rebut their claim.
Background
In 2010, Steuben Foods initiated a patent infringement lawsuit in the Western District of New York, alleging that Shibuya infringed claims of its ‘591, ‘188, and ‘985 patents. The case was transferred to the District of Delaware in 2019, where Judge Connolly denied Steuben’s motion for summary judgment—citing, among other factors, that Shibuya’s invocation of the reverse doctrine of equivalents raised a genuine issue of fact. After a jury trial in 2021, the jury found infringement and awarded Steuben over $38 million in damages. During the trial, Shibuya moved for judgment as a matter of law (JMOL) under Federal Rule of Civil Procedure 50(a) and, after the verdict, renewed its JMOL of noninfringement under Rule 50(b) for all asserted claims. The district court ultimately granted Shibuya’s renewed JMOL motion, finding that “no reasonable juror could have found infringement” of the asserted patent claims, and conditionally granted Shibuya a new trial under Rule 50(c)(1).
CAFC’s ruling
At the District Court level, Judge Connolly granted a JMOL of noninfringement in favor of Shibuya, ruling that Shibuya had made a prima facie case for noninfringement under RDOE and that Steuben’s expert testimony failed to adequately rebut this case. On appeal, Steuben argued that the 1952 Patent Act effectively eliminated RDOE, contending that if a device literally falls within a claim’s scope, any challenge regarding the claim’s breadth should be pursued as a § 112 issue rather than as a claim of noninfringement under the reverse doctrine of equivalents.
Even though they found Steuben’s arguments “compelling,” the CAFC did not rest its decision on Steuben’s RDOE contentions. Instead, it determined that the evidence was sufficient to sustain the finding of infringement without addressing the RDOE issue. As a result, the court reversed the JMOL of non-infringement and reinstated the jury’s verdict of infringement. In doing so, however, they indicated that RDOE was unlikely to stick as a defense to infringement. They made it clear that they had never “affirmed a decision finding noninfringement based on the reverse doctrine of equivalents.” [Tate Access Floors, Inc. v. Interface Architectural Res., Inc., 279 F.3d 1357, 1368 (Fed. Cir. 2002)]
What does this mean?
While the CAFC did not need to reach the merits of Steuben’s RDOE arguments to decide the case, its treatment of the doctrine suggests that its days may be numbered. The court’s reluctance to rely on RDOE, coupled with its acknowledgment that it has never affirmed a finding of noninfringement under the doctrine, signals that RDOE remains on shaky ground. Until the Federal Circuit squarely addresses its viability, RDOE exists in a state of limbo, and patent litigators should be wary of resting their defense on this uncertain doctrine.