PTAB challenges

Proceedings overview

Currently, there is one AIA trial proceeding on file for US Patent 11138997. This proceeding resulted in a discretionary denial of institution, leaving all claims of the patent untested by the PTAB. This gives a defendant a neutral-to-challenging defensive posture, as the patent's claims have not been formally challenged and upheld or invalidated in an AIA trial.

IPR2026-00015 — Resonac Hard Disk Corporation et al. v. Dieter Suess

• Type: Inter Partes Review
• Filed: 2025-10-08
• Status: Discretionary Denial (The PTAB declined to institute the review on discretionary grounds.)
• Judge panel: Not publicly available at this stage for a discretionary denial.
• Petition grounds: Details regarding specific claims, prior art, and statutory bases (§ 102 / § 103 / § 112) for the petition are not available in public records for a discretional denial.
• Institution decision: Denied on 2026-03-09. The petition was denied on procedural or discretionary grounds, meaning the Board chose not to proceed with a full review of the merits of the patentability challenge. The public record indicates a "Discretionary Denial - Procedural".
• Final Written Decision: Not issued, as institution was denied.
• Settlement / termination: The proceeding was terminated via discretionary denial of institution.
• Appeal: No appeal was made to the Federal Circuit as no Final Written Decision was issued.
• Defensive value: The discretionary denial means the patent claims have not been substantively reviewed by the PTAB. While this IPR did not invalidate any claims, the specific reasons for the discretionary denial (which are not publicly detailed here beyond "procedural") would be crucial for understanding if future IPR attempts face similar hurdles or if the grounds themselves were weak. For a defendant, this means the patent remains valid as far as the PTAB is concerned, and an IPR-based defense would need new grounds or overcome the previous discretionary denial's rationale.

Strategic summary

Currently, all claims of US11138997 (claims 1-9) remain UNTESTED by the PTAB on their merits, as the sole IPR filed, IPR2026-00015, resulted in a discretionary denial of institution. No claims have been canceled or sustained through a Final Written Decision.

Regarding the estoppel landscape, since IPR2026-00015 was denied institution on discretionary grounds rather than on the merits, it is less clear whether § 315(e)(1) or (2) estoppel would apply to the petitioner (Resonac Hard Disk Corporation et al.) or its privies for the specific grounds raised in the denied petition. Generally, if institution is denied, estoppel on "could have raised" grounds may be limited, but the petitioner might be barred from re-filing the exact same petition again. For a new defendant currently facing assertion, the full range of prior-art grounds under § 102 and § 103 (and potentially § 112 if relevant for PGR) should still be available, assuming they are not in privity with Resonac Hard Disk Corporation et al. and the denial wasn't based on the prior art itself being insufficient.

In terms of pattern signals, the single IPR filing by "Resonac Hard Disk Corporation et al." suggests a specific industry player initiated the challenge. The "Discretionary Denial - Procedural" status from the USPTO PTAB Data indicates the Board found a procedural reason not to proceed, rather than a lack of merit in the underlying patentability challenge. It is not clear if this petitioner is a defensive aggregator like Unified Patents based on the provided information, but the "et al." might suggest multiple entities.

Recommended next steps

If you are a defendant facing assertion of US11138997:

• Investigate IPR2026-00015's detailed denial reasons: The "Discretionary Denial - Procedural" is a critical but vague detail. Accessing the full record for IPR2026-00015, if available through a Freedom of Information Act (FOIA) request or if specific parties have access, would be crucial to understand the exact procedural basis for the denial. This would inform whether similar procedural issues might arise in a new IPR challenge or if the denial signals deeper issues with the petition's strategy.
• Conduct thorough prior art search: Since the claims have not been substantively reviewed, a fresh and comprehensive prior art search is warranted to identify strong invalidity contentions under § 102 and § 103, potentially targeting independent claims 1 and 7 and their dependent claims.
• Consider a new PTAB petition: If strong prior art is found and the reasons for the previous discretionary denial can be avoided or addressed, filing a new Inter Partes Review petition remains a viable defensive strategy. The statutory one-year deadline for institution from the filing date would apply.