Be Careful What You Wish For: How Stipulations Become Federal Circuit Issues

Stipulations are an important tool for simplifying patent cases. They can be used to narrow disputed issues, streamline discovery, and focus trial on what really matters. But stipulations can also take on a life of their own and must be entered into with caution and foresight. For example, stipulations can be re-read years later and used for different purposes than what originally motivated them. And recent Federal Circuit treatment shows that stipulations can become central to merits issues in patent cases on appeal.

Short-term gain can mean long-term pain

An easy-to-forget baseline rule in the rush to streamline complex patent cases is that stipulations are voluntary, but once entered into are binding and enforceable. The Federal Circuit has emphasized that a factual stipulation “fairly entered into” is controlling on the parties and generally must be enforced. Ring & Pinion Serv. Inc. v. ARB Corp., 743 F.3d 831, 836 (Fed. Cir. 2014).

A harder rule concerns interpretation. Unsurprisingly, each side often will try to read a stipulation the way that helps it most, and the fight about what the stipulation means or how it should be applied can be more expensive than any streamlining the stipulation was intended to achieve.

It is also important to keep in mind that a district court’s interpretation of a stipulation is reviewed de novo. Akamai Techs., Inc. v. Limelight Networks, Inc., 805 F.3d 1368, 1374 (Fed. Cir. 2015). This often leads to disputes over the scope of stipulations on appeal.

Maquet: Opponents may argue stipulations for appellate jurisdiction waive defenses

In Maquet Cardiovascular, LLC v. Abiomed, Inc., 131 F.4th 1330 (Fed. Cir. 2025), the parties used a familiar appellate vehicle: After claim construction, they jointly stipulated that there was no infringement under the court’s constructions. The district court entered judgment “in accordance with” the joint stipulation, allowing an immediate appeal of the claim construction issues. Id. at 1337.

On appeal, Abiomed argued that the stipulation’s phrasing itself led to waiver of Maquet’s ability to challenge the non-infringement judgment. Specifically, Abiomed argued that the Federal Circuit could affirm without reaching the disputed claim construction issues because Maquet did not appeal one portion of the construction. Id. In other words, because Maquet agreed to non-infringement based on the district court’s claim construction, but did not challenge one part of that construction, Maquet had waived its infringement case.

The Federal Circuit rejected that argument as a misreading of the parties’ stipulation, explaining that the stipulation’s “based on the Court’s construction” language logically referred to the disputed portions of claim construction, not the portion both sides agreed to, which Maquet “legally could not” challenge on appeal. Id.

Azurity: Opponents may argue undisputed facts waive claim construction positions

A claim construction-related stipulation also came up in Azurity Pharma., Inc. v. Alkem Labs., Ltd., 133 F.4th 1359 (Fed. Cir. Apr. 8, 2025). There, non-infringement turned on claim scope and prosecution history. The Federal Circuit concluded that the prosecution history contained a clear, unambiguous, and complete disclaimer as to the presence of propylene glycol in the claimed invention, and it credited the district court’s finding that Alkem’s Abbreviated New Drug Application (ANDA) product contained propylene glycol. Id. at 1367-68.

Azurity attempted to blunt that conclusion by pointing to a stipulation embedded in a pretrial list of “at least 143” undisputed facts. Id. at 1368. The disputed sentence stated: “Suitable flavoring agents for use in the Asserted Claims include flavoring agents with or without propylene glycol.” Id. Azurity argued that this meant that “Alkem surrendered its disclaimer position,” effectively equating “suitable … for use in the asserted claims” with “infringing.” Id.

The Federal Circuit rejected that reading based on three interpretive cues. First, context mattered: The “Infringement” section of the stipulation began with an express statement that the only infringement dispute in the case related to the presence of propylene glycol in Alkem’s ANDA products, making it implausible to read a later line as conceding the dispute. Id. at 1368-69. Second, the court contrasted other “undisputed facts” in the stipulation with the one at issue here. Specifically, the other undisputed facts explicitly stated that an accused product “meets” a particular claim limitation, whereas the disputed stipulation did not say any limitation was met. Id. at 1369. Third, the stipulation’s origin mattered: It emerged from a dispute about whether propylene glycol could be treated as part of the claimed “flavoring agent,” and it did not resolve whether Alkem’s ANDA actually contained a flavoring agent with propylene glycol. Id.

For these reasons, the Federal Circuit concluded that Azurity’s view of the stipulation “cannot be sustained when a far more sensible reading is the one consistent with the stipulation’s origin.” Id.

VLSI oral argument: Opponents may argue damages stipulations relate to liability

That same pressure surfaced again at oral argument in VLSI Technology, LLC v. Intel Corp., No. 2024-1772, on February 5, 2026. (Fed. Cir. oral arg. audio posted Feb. 5, 2026). In the district court, Intel won summary judgment that VLSI had not shown that any infringing activity occurred within the United States.

In the appeal argument, however, the key issue was how the Federal Circuit should read a stipulation that each party interpreted differently. VLSI pointed to the stipulation’s language that 70% of products alleged to practice the asserted patents were “deemed to have a United States nexus as required by each subsection of 35 U.S.C. § 271.” VLSI Argument at 0:58-1:20. VLSI accordingly urged that the stipulation resolved the nexus question by deeming 70% of certain Intel products and associated activities to have the U.S. nexus required by each subsection of 35 U.S.C. § 271. Thus, according to VLSI, Intel gave up its territoriality defense to infringement in exchange for substantially streamlined discovery. VLSI Argument at 1:42-4:45.

Intel, however, pointed to the context provided by the stipulation’s “whereas” clauses (including citations to the parties’ correspondence when negotiating the stipulation), as well as language in the stipulation stating that it was not an admission of patent infringement. VLSI Argument at 29:45-32:12. Intel also explained that the district court judge who was closest to the issues in the case understood that the stipulation was intended only for damages purposes and read the stipulation in Intel’s favor. Id.

Regardless of how the case is ultimately resolved, the colloquy again illustrates an important lesson with stipulations: Be clear or risk waiver. Here, an agreement designed to simplify damages discovery was recast as relieving VLSI of its obligation to prove aspects of its infringement case, even with “no admission” clauses.

Takeaways

Stipulations remain essential tools for streamlining patent disputes. But Maquet, Azurity, and the VLSI oral argument teach a valuable lesson: Parties should draft stipulations assuming there will be later disputes over their scope. Accordingly, the safest stipulation is drafted for a skeptical Federal Circuit panel years later.

A short playbook can help reduce the risk that a stipulation becomes an appellate battleground:

1. Define the purpose, phase, and scope of the stipulation. Identify what the stipulation is for, when it applies, and what products, versions, time periods, or geographies it covers. If there is any potential ambiguity, identify not only how the stipulation should be applied, but also how it should not be applied.
2. For stipulations of non-infringement to create appellate jurisdiction, draft the stipulation as a narrow jurisdictional bridge, not a broad merits concession. Identify the specific constructions being appealed, state expressly that the stipulation is entered into solely to obtain final judgment for appellate review, and reserve all infringement positions under any different constructions adopted on appeal so that remand proceeds on the merits rather than on arguments related to stipulation scope.
3. For stipulations intended to streamline a particular aspect of discovery, make that point expressly in the stipulation to avoid the need for parole evidence to resolve ambiguity and remove any language about unrelated statutes that could be used to re-cast the purpose of the stipulation.
4. Carefully guard against overly broad stipulations that can affect defenses. Add a targeted “notwithstanding” clause when a stipulation could be argued to displace a legal theory — e.g., claim construction, prosecution disclaimer, or territoriality under § 271. When a single defense turns on a single limitation, the safest stipulation is one that carries its own containment language paired, in the same paragraph, with an express carve-out stating what is not being admitted.