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The U.S. Patent and Trademark Office has proposed a significant change to ex parte reexamination (EPR) practice: third-party requesters would no longer be able to remain anonymous to the Office. In a notice of proposed rulemaking published July 22, 2026, the USPTO proposed adding 37 C.F.R. § 1.510(b)(7), which would require every third-party request for ex parte reexamination to include a statement identifying all real parties in interest. [1] Comments to the proposed rule are due by August 21, 2026. Because the Office views this as a procedural rather than substantive rulemaking, however, the proposed change could be finalized relatively quickly.

An EPR request allows anyone, a third party or even the patent owner, to ask the PTO to reexamine an issued patent’s claims based on prior patents or printed publications raising a substantial new question of patentability. A “third-party requester” is any person filing an EPR request other than the patent owner. Historically, requesters could file completely anonymously, often through a registered patent attorney or agent acting as the named filer, so neither the public nor the patent owner knew who was actually behind a challenge.

New Requirement

The PTO’s proposal would not necessarily make requester identity public. A requester could still request that the real-party-in-interest statement be kept confidential, and the USPTO would exclude that statement from the publicly available patent file. But confidential is not the same as anonymous, and the PTO itself would know who is behind the request even if the public, the patent owner, and competitors do not.

The identification of “all real parties in interest” is a meaningful departure from historical ex parte reexamination practice. Under 35 U.S.C. § 302, “any person” may request reexamination of an issued patent based on patents or printed publications that raise a substantial new question of patentability, and § 301(e) permits a person submitting prior art to keep their identity confidential. By contrast, inter partes review (IPR) and post-grant review (PGR), which are other administrative procedures for challenging a patent, have always required transparency as to real parties in interest. Specifically, 35 U.S.C. § 312(a)(2) permits the Office to consider an IPR petition only if the petition identifies all real parties in interest. The proposed rule would move EPRs closer to the IPR model.

Rationale for Proposed Change 

The requirement to disclose requester identity matters because of estoppel. Under 35 U.S.C. §§ 315(e)(1) and 325(e)(1), a party that loses on the merits in an IPR or post-grant review (PGR), along with its real parties in interest and privies, is barred from later raising, in another USPTO proceeding or in court or before the ITC, any patentability ground it raised or reasonably could have raised. In practice, this means a party cannot get a second bite at invalidating a patent using arguments already dismissed, or which could have been raised. Without identifying real parties in interest in an EPR, a losing IPR or PGR petitioner could potentially circumvent that estoppel by having an anonymous EPR request filed on its behalf.

The current proposal is not new. The USPTO proposed the same requirement in 2012 during implementation of the America Invents Act, but dropped it in the final rule after comments expressed concern that mandatory identification would have a chilling effect on the filing of reexamination requests. The PTO has now revived the idea in a very different environment, where IPR access has been narrowed by the recent increase in IPR petition denials, making EPR an increasingly attractive alternative vehicle for patent challenges.

The proposal is also linked to a separate, pending PTAB rulemaking that would add 37 C.F.R. § 42.108(e)(5), letting the Board deny institution of an IPR where the same real party in interest had earlier filed an anonymous EPR request against the same patent. Commenters have noted that provision cannot function without real-party disclosure in EPR itself. The USPTO also points to concerns about fraudulent or misleading certifications and could issue show-cause orders where a party misrepresents its real-party-in-interest status.

It is interesting to consider this proposed change against the backdrop of recent statistics comparing the number of EPRs filed versus IPRs and PGRs. As seen from the following table, the number of ex parte reexaminations (EPRs) has been increasing and far exceeds the number of IPRs and PGRs combined over comparable periods. This data begs the question whether the proposed change could trigger a shift away from EPRs to IPRs or PGRs.

Impact on Stakeholders

For requesters, the practical burden may be greater than the USPTO suggests. The Office describes the added burden as de minimis, but determining who qualifies as a real party in interest can be fact-intensive. Federal Circuit and Supreme Court decisions have shown that real-party and privity questions may turn on control, funding, relationships, strategic coordination, and other case-specific facts. [2] Those questions have been hotly contested in many IPR proceedings. Under the proposed rule, a requester would have to make that determination correctly at the outset of reexamination or risk filing-date consequences and possible challenges to certifications made to the Office.

Patent owners may welcome the rule as a transparency and estoppel-enforcement measure, since it will let them identify who is actually challenging their patents and assert estoppel where applicable. Knowing the true opponent can also inform settlement and licensing strategy. Third-party challengers and accused infringers, who have often filed EPR requests through registered practitioners specifically to preserve anonymity, will find that this practice no longer shields their identity from the Office, even though it may still keep their identity out of the public record. Moreover, although it is early to speculate, there is real concern about the potential loss of requested confidentiality in response to future subpoenas or litigation.

Practical Takeaways

1. Assess real-party-in-interest issues early, before filing an EPR.
2. Document the basis for any real-party-in-interest determination, in case it is later challenged.
3. Remember that a confidentiality request keeps identity out of the public file, not out of the USPTO’s knowledge.
4. Weigh EPR against IPR or PGR options strategically, accounting for disclosure obligations and estoppel exposure in each forum.

[1] The rulemaking notice is listed as Docket No. PTO-P-2025-0545 and RIN 0651-AD94.

[2] Applications in Internet Time, LLC v. RPX Corp., 897 F.3d 1336 (Fed. Cir. 2018); Taylor v. Sturgell, 553 U.S. 880 (2008).