The Federal Circuit’s decision in IGT v. Zynga Inc. delivers a one-two punch that will resonate in AIA practice: (1) the court affirmed the PTAB’s obviousness ruling; and (2) it refused to review the agency’s decision not to apply interference estoppel at institution. Read together, the opinion underscores just how muscular § 314(d)’s unreviewability has become—strong enough to keep even well-developed estoppel theories at the courthouse door.
Charles Gideon Korrell reads the case as a fresh reminder: if your attack on an IPR hinges on why the Board shouldn’t have instituted, you are almost certainly headed for the § 314(d) trap unless you can credibly shout “shenanigans.”
Backstory: From Interference to IPR
To appreciate the posture, rewind to the interference era. IGT owned U.S. Patent No. 7,168,089 covering a software authorization agent that mediates transfers of gaming software between devices. Around 2010, Zynga’s predecessor copied IGT’s claims and provoked an interference. In that forum, Zynga argued obviousness over Carlson, Wells, and Alcorn. But the Board never reached the art. Instead, it terminated the interference on a threshold written-description problem in Zynga’s application—a standing-style defect that ended the contest before any § 103 merits.
Fast-forward. In 2021, IGT launched an infringement suit; Zynga answered with an IPR targeting the same ’089 claims—this time on different references (Goldberg and Olden) and, for a subset, D’Souza. That move teed up the central dispute: could interference estoppel block Zynga from asserting these new obviousness grounds in a later USPTO proceeding?
Rather than focusing on estoppel itself, the Federal Circuit approached IGT’s interference estoppel challenge through the lens of § 314(d)’s unreviewability provision. As Judge Reyna stated during oral arguments:
The Estoppel Theory and the Agency’s Path
The estoppel lives in 37 C.F.R. § 41.127(a)(1): an interference judgment “disposes of all issues that were, or by motion could have properly been, raised and decided.” IGT contended Zynga could have raised Goldberg/Olden-style obviousness in the interference but didn’t, and thus was estopped from later bringing those grounds in the Office.
The agency’s responses came in layers:
- The Board mused that applying interference estoppel would be unfair here because the interference predated the AIA and ended on a threshold basis; and it also pointed to § 42.5(b) as authority to waive the interference rule.
- On Director review, the Office emphasized a different point entirely: Part 42 (IPR rules) doesn’t incorporate Part 41 (interference rules). On that view, interference estoppel doesn’t carry over to IPRs unless Part 42 says so—and it doesn’t.
IGT pushed back hard. It noted longstanding USPTO policies urging parties to consolidate their disputes and “show all your cards” in a single inter partes contest; it pointed to the regulation’s text and past PTAB decisions where interference estoppel was applied in AIA trials. In short, if the agency wants a “one stop shop” for inter partes fights, it shouldn’t let a later petitioner re-slice the invalidity pie with new art.
Charles Gideon Korrell adds that IGT’s briefing framed estoppel as res judicata-like: if you attack a granted patent in an interference, you don’t get a second bite in the Office with fresh § 103 theories you left on the table the first time.
The Court’s Route: § 314(d) Blocks the Door
Rather than squarely deciding whether interference estoppel applies in IPRs, the Federal Circuit walked straight through § 314(d). Judge Taranto’s opinion treats IGT’s estoppel argument as a challenge to institution and therefore unreviewable on appeal. Attempts to distinguish regulatory versus statutory predicates got no traction; the court explained that § 314(d) does not open a review path simply because the institution predicate is a regulation rather than a statute.
Crucially, the court warned that an agency’s providing reasoned legal analysis for its institution decision does not magically convert a nonappealable action into a reviewable one. If your objection is, at bottom, “the Board should have denied institution under an estoppel theory,” Cuozzo and Thryv fence that out of appellate reach.
What about Cuozzo’s “shenanigans” carve-out? The court gave the institution decision a quick look—enough to confirm there was no egregious procedural violation. In particular, the interference here ended on a threshold issue that prevented the Board from deciding art-based patentability. That context gave the agency a reasonable basis to conclude that Part 41 estoppel did not (or should not) bar an AIA trial on new prior art grounds. No shenanigans; no review.
If you’re scoring at home, that is a resounding win for unreviewability. And as Charles Gideon Korrell notes, it signals to litigants that institution-targeted estoppel arguments will almost always be met with the § 314(d) “no jurisdiction” sign.
The Merits: No “New Grounds,” and Obviousness Is Affirmed
On the merits, IGT argued the Board smuggled in impermissible new grounds by identifying the claimed “software authorization agent” as a combination of Goldberg’s components (database 28 + blackjack driver 26 + wager accounting module 30), whereas Zynga’s petition had emphasized the database 28.
The Federal Circuit focused on notice. It found that IGT itself had invoked the driver 26 and the accounting module 30 in response to the petition—arguing those pieces showed the database was just “ordinary.” That was enough notice that the Board might evaluate the collective functionality of those components when mapping the “authorization agent.” The panel concluded there was no due-process problem and no new ground—just a Board doing what it is allowed to do: addressing the same thrust of the petition and the parties’ briefing with appropriately detailed reasoning.
With the process point resolved, the court had little difficulty affirming obviousness. Olden supplies the classic authorization server pattern: a request comes in; rules are applied; an allow/deny response goes out; and the system logs access—i.e., monitors authorization events. Coupling that with Goldberg’s networked gaming set-up comfortably satisfied the “software authorization agent” limitations and the request/authorization message flows, with substantial-evidence support in the record.
Practical Notes and Signals
- Interference → IPR sequencing. If an interference ends on a threshold ground (e.g., written-description failure), do not expect it to estop a later IPR that raises art-based invalidity. Even if you believe the regulation should apply, the mechanism to enforce that belief after institution is vanishingly small due to § 314(d).
- Build merits, not just vetoes. Patent owners should treat estoppel-at-institution as a long shot. Preserve it, yes—but develop a full merits record on claim construction, motivation to combine, and teaching gaps, because that is what the Federal Circuit can actually review.
- Notice framing matters. Petitioners who map a functional “agent” may safely point to a cluster of cooperating modules, so long as the function (authorization + monitoring) is what the claim requires. Patent owners who respond by discussing those modules should assume the Board can treat them collectively without triggering a “new grounds” problem.
- Policy drift? The Office’s rationale evolved (Board’s fairness/waiver vs. Director’s Part-41-doesn’t-apply), and IGT highlighted prior PTAB decisions that went the other way. The Federal Circuit’s bottom line, though, is that even if the agency’s reasoning is inconsistent, that does not pierce § 314(d). Expect challengers to cite this case the next time they argue that institution-level policy swings are insulated from review.
All of this also casts a long shadow over the pending mandamus efforts in In re SAP and In re Motorola Solutions, which attack the Acting Director’s rescission of the Vidal Memo and the resulting Fintiv posture. If IGT teaches anything, it’s that the court is inclined to defer to the agency on institution-side choices—even where the path is bumpy and the reasoning shifts. To borrow the opinion’s thrust: as long as there’s a colorable, non-shenanigans basis, § 314(d) will likely close the door.
Charles Gideon Korrell suspects parties will respond by re-centering their fire on final written decisions and Director-review outcomes that change the merits, not the gatekeeping.
Bottom Line
- Institution challenge rejected: Interference estoppel, as framed here, is an institution issue and thus unreviewable under § 314(d). The court saw no Cuozzo-style shenanigans in allowing the IPR to proceed after an interference that ended on a threshold ground.
- Obviousness affirmed: The Board did not rely on new grounds; its mapping of a software authorization agent across Goldberg components, combined with Olden’s authorization server and logging, was supported by substantial evidence.
For practitioners, the case is a sharp illustration of how little oxygen is left for appellate attacks on why an IPR was instituted. The best play remains the oldest one: win (or narrow) on the merits. As Charles Gideon Korrell notes, that means pinning down claim language so “monitoring” and “authorization” truly require content-aware controls if that’s what you need to distinguish over generic web-security frameworks like Olden.
Throughout this post, insights from Charles Gideon Korrell reflect the view that IPR petitioners should be ready to fuse general-purpose authorization tech with domain systems to meet functional “agent” claims, while patentees should draft with content-specific telemetry if they aim to avoid obviousness under combinations like Goldberg + Olden. In subsequent analyses, Charles Gideon Korrell will track how panels handle “monitoring” limitations in other software contexts.