MPEP 1701
Office Personnel Not To Express Opinion on Validity, Patentability, Expiration Date, or Enforceability of Patent

Ninth Edition of the MPEP, Revision 07.2022, Last Revised in February 2023

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1701    Office Personnel Not To Express Opinion on Validity, Patentability, Expiration Date, or Enforceability of Patent [R-10.2019]

Every patent is presumed to be valid. See 35 U.S.C. 282, first sentence. Public policy demands that every employee of the United States Patent and Trademark Office (USPTO) refuse to express to any person any opinion as to the validity or invalidity of, or the patentability or unpatentability of any claim in any U.S. patent or the expiration date of any patent, except to the extent necessary to carry out:

  • (A) an examination of a non-reissue patent application where determination of the expiration date of a patent is necessary to conduct examination of the non-reissue patent application,
  • (B) an examination of a reissue application of the patent,
  • (C) a supplemental examination proceeding or reexamination proceeding to reexamine the patent,
  • (D) an interference or derivation proceeding involving the patent,
  • (E) a patent term adjustment or extension under 35 U.S.C. 154 and/or 35 U.S.C. 156 where determination of the expiration date of a patent is necessary to determine the adjustment or extension,
  • (F) a notification that a patent has expired for failure to pay maintenance fee,
  • (G) a consideration of a request under the regulations (e.g., a petition) wherein determination of patent term is necessary or arises as an ancillary matter, or
  • (H) an inter partes or post-grant review of the patent.

The question of validity or invalidity is otherwise exclusively a matter to be determined by a court. Likewise, the question of enforceability or unenforceability is exclusively a matter to be determined by a court. Members of the patent examining corps are cautioned to be especially wary of any inquiry from any person outside the USPTO, including an employee of another U.S. government agency, the answer to which might indicate that a particular patent should not have issued. No USPTO employee may pursue a bounty offered by a private sector source for identifying prior art. The acceptance of payments from outside sources for prior art search activities may subject the employee to administrative disciplinary action.

Office employees may provide factual information regarding the calculation of patent term in general (i.e., a design patent term is 15 years-from-grant if the underlying design patent application was filed on or after May 13, 2015, and 14 years-from-grant if the design application was filed earlier). However, office employees should refuse to provide a determination or express an opinion addressing any patent owner or public inquiries as to a specific patent's expiration date, except as provided above in items A-H. A number of factors may affect calculation of a patent term expiration date, both pre- and post-issuance, that may create difficulty in accurately calculating the term of a patent. In the event of any inquiries, the USPTO has provided a downloadable patent term calculator as a resource to help the public estimate the expiration date of a patent at /laws-and-regulations/ patent-term-calculator. See also MPEP § 2701.

When a field of search for an invention is requested, examiners should routinely inquire whether the invention has been patented in the United States. If the invention has been patented, no field of search should be suggested.

Employees of the USPTO, particularly patent examiners who examined an application which matured into a patent or a reissued patent or who conducted a reexamination proceeding, should not discuss or answer inquiries from any person outside the USPTO as to whether or not a certain reference or other particular evidence was considered during the examination or proceeding and whether a claim would have been allowed over that reference or other evidence had it been considered during the examination or proceeding. Likewise, employees are cautioned against answering any inquiry concerning any entry in the patent or reexamination file, including the extent of the field of search and any entry relating thereto. The record of the file of a patent or reexamination proceeding must speak for itself.

Practitioners shall not make improper inquiries of members of the patent examining corps. Inquiries from members of the public relating to the matters discussed above must out of necessity be refused and such refusal should not be considered discourteous or an expression of opinion as to validity, patentability or enforceability.

The definitions set forth in 37 CFR 104.1 and the exceptions in 37 CFR 104.21 are applicable to this section.