What the USPTO’s Reexamination Remand for HID Means for Estoppel, Timing and Strategy

The U.S. Patent and Trademark Office (USPTO) issued a significant Decision on Remand on Monday, April 27, 2026, clarifying when estoppel under 35 U.S.C. § 315(e)(1) attaches and—critically—what it means to “request” a proceeding “before the Office.” The ruling arises from an increasingly common set of circumstances—HID had initially filed an inter partes review (IPR) against CPC Patent Technologies’ U.S. Patent No. 9,665,705, and subsequently requested ex parte reexamination requests of that same patent. Monday’s decision clarifies that a party is estopped from “requesting” ex parte reexam at the moment the IPR final written decision issues when the USPTO has yet to order ex parte reexam.

Underpinning the HID Decision is the Office’s reinterpretation of the word “request” in Section 315(e)(1). U.S. patent law bars a petitioner (or its privies/real parties in interest) from “request[ing] or maintain[ing] a proceeding before the Office” with respect to claims addressed in a prior IPR final written decision on grounds that were or reasonably could have been raised.

On remand, the Office drew a bright line defining two distinct time periods:

(1) the period from filing a request for ex parte reexam up to the Director’s order of reexamination under Section 304, and

(2) the period after that Section 304 order. During the first period, the Office is considering a request, nothing more.

The reexamination “proceeding” begins only after the Director’s Section 304 order. In fact, prior to that Section 304 order, there is not even a “proceeding” to be “maintained.” That position carefully maintains consistency with the Office’s prior statements (e.g., in its briefing in In re Gesture Technology Partners) that Section 315 estoppel does not bar the Office’s maintenance of an already-ordered ex parte reexamination, while addressing prior MPEP language that loosely referred to the pre-order phase as a “pending proceeding.”

The crucial shift is that “request” is now read as a verb covering the entire act of asking the Office to commence reexamination—not just the moment of filing the papers. Accordingly, the “request” period runs from filing through the Section 303 decision window (up to three months by statute). The Office interpreted “request” in Section 315(e)(1) to encompass both the instant of filing and the pre-order interval before the Director’s Section 304 order. As a consequence, 315(e)(1) estoppel can bar the act of requesting if a final written decision issues during that interval. That is precisely what doomed HID’s request here: the IPR final written decision arrived on August 13, 2024—four days after HID filed for ex parte reexam, but before the Directors’ November 4, 2024, order granting reexamination. Because the IPR final written decision issued before reexamination was ordered, Section 315(e)(1) barred HID from “requesting” reexamination.

This decision tightens the timing window for “IPR-then-reexam” tactics. Petitioners can no longer bank on filing a reexamination request during pendency of an IPR (e.g., after gauging the PTAB panel during oral argument) and securing an order before a final written decision issues. If a final written decision lands during the Section 303 window, the request can be barred. For in-house teams coordinating multi-track challenges, this raises the premium on front-loading prior art in the IPR petition and being realistic about Director Review risks, appeals, remands, and panel outcomes.

What’s next:

• Although a petition to the Director is permitted within one month of denial under Rule 1.515(c), one would presume that the Director’s office was at least apprised of this Decision, g., in view of the previous HID litigation and the surge in ex parte reexamination requests (including serial requests following IPRs).
• Instead, it seems more likely that HID will file another Administrative Procedures Act suit in the U.S. District Court for the Eastern District of Virginia challenging the Office’s decision that reexamination is barred by the estoppel provisions.
• The HID Decision anecdotally seems to have released a logjam of ex parte review decisions (g., in Control Nos. 90/015,948 & 90/015,949) raising similar issues.
• The HID Decision tightened the window for making serial challenges, but didn’t totally close it. We may see ex parte reexamination requests filed earlier in IPRs (g., around the time for requesting oral argument, which is typically about five months before the statutory deadline for the PTAB to issue a Final Written Decision).

Image Source: Deposit Photos
Author: bradcalkins
Image ID: 7477730