PTAB challenges

Proceedings overview

There is one AIA trial proceeding on file for US Patent 9666732, with a status of Discretionary Denial. This indicates the patent's claims have not been substantively challenged and remain intact, presenting a stronger defensive posture for the patent owner against future challenges based on the grounds that could have been raised in this petition.

IPR2025-01411 — Mundra Solar PV Limited v. Tetrasun Inc

• Type: Inter Partes Review
• Filed: 2025-08-15
• Status: Discretionary Denial – The PTAB declined to institute the IPR.
• Judge panel: Not publicly available from the provided data.
• Petition grounds: Not publicly available from the provided data.
• Institution decision: Denied. The petition was denied institution on 2026-01-13. The reason for the denial was procedural, specifically a Discretionary Denial.
• Final Written Decision: Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: Not applicable, as institution was denied.
• Defensive value: The patent owner successfully fended off an IPR challenge on procedural grounds. This means the claims of US9666732 have not been substantively reviewed by the PTAB in this proceeding, and an IPR-based defense using the same or similar grounds would likely face the same discretionary denial.

Strategic summary

Currently, all claims of US9666732 remain UNTESTED by a full PTAB trial. The single IPR filed, IPR2025-01411, was denied institution on discretionary grounds, meaning the merits of the patentability challenge were not evaluated. This leaves all claims of the patent, as issued, in full force.

The estoppel landscape is relatively clear. While a discretionary denial can involve various factors, if the denial was based on factors that could reasonably have been foreseen or addressed by the petitioner, subsequent petitioners (and their privies) might face an uphill battle trying to institute an IPR on the same or substantially similar prior art or arguments. However, the exact grounds raised in the petition are not public, so the full scope of potential estoppel is unclear.

The involvement of Unified Patents as a source for litigation and PTAB data signals that they are monitoring the patent. Their listing of IPR2025-01411 with a "Not Instituted - Procedural" status suggests an interest in patent quality or defensive aggregation, although they are listed as a source of information rather than the petitioner in the provided PTAB data. Mundra Solar PV Limited was the petitioner in IPR2025-01411.

Recommended next steps

If you are a defendant facing assertion of US9666732, you should note that no claims have been invalidated by the PTAB. The denial of IPR2025-01411 on discretionary grounds suggests that a strong procedural argument was successfully made by the patent owner. Any new IPR petition would need to carefully consider the reasons for the prior discretionary denial to avoid a similar outcome.

The PTAB case IPR2025-01411 was denied institution on 2026-01-13. Details of the discretionary denial can be found on the USPTO PTAB Decisions portal by searching for IPR2025-01411.