TAKEAWAY: Under the USPTO’s new U.S. counsel rule, whether an unsigned paper from a foreign-domiciled applicant or patent owner can be corrected later or is lost for good depends on what the paper is and when it was due.
As of July 20, 2026, there is a new requirement that patent applicants and owners whose domicile is not located within the U.S. or its territories must be represented by a registered patent practitioner. A registered practitioner is a registered patent attorney, a registered patent agent, or an individual who has received limited recognition by the United States Patent and Trademark Office (the “Patent Office”). The new requirement applies to all papers received in patent matters on or after July 20, 2026, regardless of the filing date of the application.
Domicile is defined as the permanent legal place of residence of a natural person or the principal place of business of a juristic entity. Domicile is not related to citizenship, so a U.S. citizen living abroad may be foreign-domiciled, while a foreign national living in the U.S. may not be. The Patent Office will normally determine domicile from the residence and address information in the Application Data Sheet. If even one applicant or patent owner is foreign-domiciled, representation is required. Companies and other juristic entities have been required to be represented in patent applications by a registered patent practitioner, regardless of the domicile of the applicant, since September 16, 2012, and the new rule extends this requirement to patent owners that are juristic entities, such as for post-grant papers.
The consequences of failing to comply with the rule depend on the paper. The rule does not change the requirements to receive a filing date, so an application filed by a foreign-domiciled applicant will still receive a filing date, for example. However, an Application Data Sheet that is not signed by a practitioner will be treated as a transmittal letter. Thus, for example, the inventorship will not be set, and the priority or benefit claims will not take effect. Similarly, a micro entity certification signed by a foreign-domiciled inventor or applicant will not be accepted. These defects can generally be corrected after filing, although a priority or benefit claim must be corrected within a set time period, generally the later of four months from the filing date or sixteen months from the filing date of the earlier application. After that period, the claim can be restored only by a petition to accept an unintentionally delayed claim, which requires a petition fee.
Under a separate rule change effective August 13, 2026, the petition may also require an explanation of the delay and a higher petition fee if filed more than one year after the claim was due. Other defects cannot be corrected, however. For example, a nonpublication request or a request for prioritized examination must be made at the time of filing in that application, and may be permanently lost if not properly signed on the filing date.
The new rule also applies to issued patents. According to the Patent Office, when it is necessary to act on a paper filed in an issued patent and the paper is not signed by a registered practitioner, the paper may not be treated on its merits. So, for example, a petition to accept an unintentionally delayed maintenance fee payment under 37 CFR 1.378(b) that is not signed by a registered practitioner may be dismissed. This is so even though payment of the maintenance fee itself is expressly excluded from the rule. Thus, a foreign-domiciled patent owner may pay a maintenance fee on time without a practitioner, but a petition to accept a late payment should be signed by a registered practitioner or it risks dismissal. The Patent Office has also confirmed that the rule applies to ex parte reexamination and examiner interviews.
The Patent Office’s guidance does not specifically address other patent-owner filings, such as certificates of correction, statutory and terminal disclaimers, reissue applications, and supplemental examination requests. Thus, it is not clear whether these filings require a practitioner’s signature. However, the general principle suggests that they may, and the more cautious approach is to have a registered practitioner sign any filings in a patent. The rule does not apply to papers that must be signed by a specific party, such as the inventor’s oath or declaration.
As a result of the new rule, foreign-domiciled applicants and patent owners, and the foreign counsel who work with them, should confirm the domicile of the parties in their U.S. matters, including issued patents. Foreign applicants and patent owners may also want to ensure that time-sensitive papers are signed by a registered practitioner, particularly papers that must be filed with the application itself.
More information is available on the Patent Office’s U.S. Counsel Rule for Patent Applications and Patents page.