Ex parte reexamination requests ask the US Patent and Trademark Office (USPTO or Patent Office) to reexamine issued patents and determine whether they should have been granted. These requests are based on prior art, typically prior art the Patent Office did not consider during the initial examination. Third parties seeking to challenge an issued patent through ex parte reexamination may currently file anonymously, which can offer strategic advantages depending on the circumstances. But as requests for ex parte reexamination increase, the Patent Office is developing new ways to determine which requests should proceed. For prospective third-party requesters, a significant consequence of the proposed rule is the potential loss of anonymity, at least before the Patent Office, which may affect strategies for post-grant challenges or other efforts to challenge patents without revealing a competitive interest.
On July 22, 2026, the Patent Office published a notice proposing to amend its rules of practice to require a third-party request for ex parte reexamination to include a statement identifying all real parties in interest to the request. The proposal comes as the Patent Office is receiving a significant number of reexamination requests directed to patents previously challenged in inter partes review or post-grant review proceedings. The proposed requirement is intended to help the Patent Office evaluate statutory estoppel provisions and respond to false certifications, misrepresentations, and fraud.
Under existing regulations, a requester may use a registered practitioner to file anonymously, certify that the requester is not subject to statutory estoppel arising from prior inter partes review or post-grant review proceedings involving the patent, and keep the real party in interest concealed from the patent owner, the Patent Office, and the general public. That anonymity, however, creates a challenge in enforcing an estoppel bar in the reexamination context because the Patent Office does not know who is behind a given request. Under the proposed rule, the Patent Office would require identification of the requester and any other real parties in interest to the reexamination request, while allowing requesters to submit those identities confidentially to the Patent Office upon request. As a result, requesters may still be able to shield their identities from the patent owner and the general public. It remains unclear, however, how the Patent Office would issue any decision indicating estoppel without identifying the requester.
If the requester or a codefendant has an adversarial history with the patent owner, disclosure of real parties in interest would create a record the Patent Office can use to evaluate estoppel and discretion. Requesters should work with practitioners to carefully assess real parties in interest before filing or supporting a reexamination request.
Comments on the proposed rule must be received by August 21, 2026. If anonymity is material to the decision to file a reexamination request, prospective requesters may consider filing before the rule is finalized. If you have questions or would like to discuss how this rule may affect your patent strategy or ongoing matters, please contact a member of McCarter’s patent group.
Proposed Rule
Document Citation 91 FR 46038