MPEP § 409.03(f) — Proof of Proprietary Interest (Annotated Rules)

§409.03(f) Proof of Proprietary Interest

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 409.03(f), including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Proof of Proprietary Interest

This section addresses Proof of Proprietary Interest. Primary authority: 35 U.S.C. 118, 37 CFR 1.47(b), and 37 CFR 3.73(b). Contains: 7 requirements, 4 guidance statements, 1 permission, and 1 other statement.

Key Rules

Topic

Assignee as Applicant Signature

11 rules
StatutoryRequiredAlways
[mpep-409-03-f-a6cc1ec7f132d075ea38e2e9]
Applicant Must Prove Proper Assignment or Interest
Note:
The pre-AIA 37 CFR 1.47(b) applicant must demonstrate that the invention has been assigned to them, the inventor has agreed in writing to assign it, or they have a sufficient proprietary interest.
When an application is deposited pursuant to pre-AIA 37 CFR 1.47(b), the pre-AIA 37 CFR 1.47(b) applicant must prove that
  • (A) the invention has been assigned to the applicant, or
  • (B) the inventor has agreed in writing to assign the invention to the applicant, or
  • (C) the applicant otherwise has sufficient proprietary interest in the subject matter to justify the filing of the application.
Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryInformativeAlways
[mpep-409-03-f-16e65740a993028486b98508]
Applicant Must Demonstrate Sufficient Proprietary Interest for Pre-AIA 37 CFR 1.47(b) Application
Note:
The pre-AIA 37 CFR 1.47(b) applicant must prove they have sufficient proprietary interest in the subject matter to justify filing the application.

When an application is deposited pursuant to pre-AIA 37 CFR 1.47(b), the pre-AIA 37 CFR 1.47(b) applicant must prove that

(C) the applicant otherwise has sufficient proprietary interest in the subject matter to justify the filing of the application.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryRequiredAlways
[mpep-409-03-f-22da6b2c5b1369061c521e3e]
Assignment of Pre-AIA Application Must Be Clearly Indicated
Note:
The assignment document must clearly state that the invention in a pre-AIA application was assigned to the original applicant.

If the application has been assigned, a copy of the assignment (in the English language) must be submitted. The assignment must clearly indicate that the invention described in the pre-AIA 37 CFR 1.47(b) application was assigned to the pre-AIA 37 CFR 1.47(b) applicant. A statement under pre-AIA 37 CFR 3.73(b) by the assignee must also be submitted (see MPEP § 324). An assignment of an application and any “reissue, division, or continuation of said application” does not itself establish an assignment of a continuation-in-part application. In re Gray, 115 USPQ 80 (Comm’r Pat. 1956). An assignment to a pre-AIA 37 CFR 1.47(b) applicant for the sole purpose of obtaining a filing date for a pre-AIA 37 CFR 1.47(b) application is not considered an assignment within the meaning of pre-AIA 35 U.S.C. 118 and pre-AIA 37 CFR 1.47(b).

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryInformativeAlways
[mpep-409-03-f-a042a93e523ef86dc578b357]
Assignment for Filing Date Not Considered an Assignment
Note:
An assignment made solely to obtain a filing date is not considered an assignment under pre-AIA laws.

If the application has been assigned, a copy of the assignment (in the English language) must be submitted. The assignment must clearly indicate that the invention described in the pre-AIA 37 CFR 1.47(b) application was assigned to the pre-AIA 37 CFR 1.47(b) applicant. A statement under pre-AIA 37 CFR 3.73(b) by the assignee must also be submitted (see MPEP § 324). An assignment of an application and any “reissue, division, or continuation of said application” does not itself establish an assignment of a continuation-in-part application. In re Gray, 115 USPQ 80 (Comm’r Pat. 1956). An assignment to a pre-AIA 37 CFR 1.47(b) applicant for the sole purpose of obtaining a filing date for a pre-AIA 37 CFR 1.47(b) application is not considered an assignment within the meaning of pre-AIA 35 U.S.C. 118 and pre-AIA 37 CFR 1.47(b).

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryRequiredAlways
[mpep-409-03-f-9d16e138db4b0e94da13b7ea]
Statement of Facts for Conditional Assignments
Note:
If an assignment agreement depends on specific conditions, it must be supported by a statement from someone with firsthand knowledge confirming those conditions were met.

When an inventor has agreed in writing to assign an invention described in an application deposited pursuant to pre-AIA 37 CFR 1.47(b), a copy of that agreement should be submitted. If an agreement to assign is dependent on certain specified conditions being met, it must be established by a statement of facts by someone with first hand knowledge of the circumstances in which those conditions have been met. A typical agreement to assign is an employment agreement where an employee (nonsigning inventor) agrees to assign to his or her employer (pre-AIA 37 CFR 1.47(b) applicant) all inventions made during employment. When such an agreement is relied on, it must be established by a statement of a person having firsthand knowledge of the facts that the invention was made by the employee while employed by the pre-AIA 37 CFR 1.47(b) applicant.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryInformativeAlways
[mpep-409-03-f-69d7de4aa2089a3487764494]
Requirement for Employee Assignment Agreement
Note:
An employee must agree in writing to assign all inventions made during employment to the employer.

When an inventor has agreed in writing to assign an invention described in an application deposited pursuant to pre-AIA 37 CFR 1.47(b), a copy of that agreement should be submitted. If an agreement to assign is dependent on certain specified conditions being met, it must be established by a statement of facts by someone with first hand knowledge of the circumstances in which those conditions have been met. A typical agreement to assign is an employment agreement where an employee (nonsigning inventor) agrees to assign to his or her employer (pre-AIA 37 CFR 1.47(b) applicant) all inventions made during employment. When such an agreement is relied on, it must be established by a statement of a person having firsthand knowledge of the facts that the invention was made by the employee while employed by the pre-AIA 37 CFR 1.47(b) applicant.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryRequiredAlways
[mpep-409-03-f-013a090ada8d5a572ad5e027]
Statement Required for Employee Invention Assignment
Note:
A statement from someone with firsthand knowledge must be submitted to establish that an employee's invention was made while employed by the pre-AIA 37 CFR 1.47(b) applicant.

When an inventor has agreed in writing to assign an invention described in an application deposited pursuant to pre-AIA 37 CFR 1.47(b), a copy of that agreement should be submitted. If an agreement to assign is dependent on certain specified conditions being met, it must be established by a statement of facts by someone with first hand knowledge of the circumstances in which those conditions have been met. A typical agreement to assign is an employment agreement where an employee (nonsigning inventor) agrees to assign to his or her employer (pre-AIA 37 CFR 1.47(b) applicant) all inventions made during employment. When such an agreement is relied on, it must be established by a statement of a person having firsthand knowledge of the facts that the invention was made by the employee while employed by the pre-AIA 37 CFR 1.47(b) applicant.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryRequiredAlways
[mpep-409-03-f-76b4a6dd4c5081c515f24f68]
Applicant Must Demonstrate Sufficient Proprietary Interest in Unassigned Invention
Note:
The pre-AIA 37 CFR 1.47(b) applicant must show they have a sufficient proprietary interest if the invention has not been assigned or there is no written agreement to assign.

If the invention has not been assigned, or if there is no written agreement to assign, the pre-AIA 37 CFR 1.47(b) applicant must demonstrate that he or she otherwise has a sufficient proprietary interest in the matter.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryPermittedAlways
[mpep-409-03-f-844b596731cb7b36c71befa6]
Proof of Proprietary Interest for Pre-AIA Applicant
Note:
Demonstrate a proprietary interest through a legal memorandum and affidavit, signed by an attorney, showing a court would award the invention to the pre-AIA applicant.

A proprietary interest obtained other than by assignment or agreement to assign may be demonstrated by an appropriate legal memorandum to the effect that a court of competent jurisdiction (federal, state, or foreign) would by the weight of authority in that jurisdiction award title of the invention to the pre-AIA 37 CFR 1.47(b) applicant. The facts in support of any conclusion that a court would award title to the pre-AIA 37 CFR 1.47(b) applicant should be made of record by way of an affidavit or declaration of the person having firsthand knowledge of same. The legal memorandum should be prepared and signed by an attorney at law familiar with the law of the jurisdiction involved. A copy (in the English language) of a statute (if other than the United States statute) or a court decision (if other than a reported decision of a federal court or a decision reported in the United States Patents Quarterly) relied on to demonstrate a proprietary interest should be made of record.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAPTAB Jurisdiction
StatutoryRecommendedAlways
[mpep-409-03-f-32f4f1fd62af2a6fa621f069]
Affidavit Required for Proprietary Interest
Note:
An affidavit or declaration from someone with firsthand knowledge must be submitted to support a claim of proprietary interest in an invention.

A proprietary interest obtained other than by assignment or agreement to assign may be demonstrated by an appropriate legal memorandum to the effect that a court of competent jurisdiction (federal, state, or foreign) would by the weight of authority in that jurisdiction award title of the invention to the pre-AIA 37 CFR 1.47(b) applicant. The facts in support of any conclusion that a court would award title to the pre-AIA 37 CFR 1.47(b) applicant should be made of record by way of an affidavit or declaration of the person having firsthand knowledge of same. The legal memorandum should be prepared and signed by an attorney at law familiar with the law of the jurisdiction involved. A copy (in the English language) of a statute (if other than the United States statute) or a court decision (if other than a reported decision of a federal court or a decision reported in the United States Patents Quarterly) relied on to demonstrate a proprietary interest should be made of record.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAAIA vs Pre-AIA Practice
StatutoryRecommendedAlways
[mpep-409-03-f-04a844fac135ba16a26d6ab0]
Copy of Statute or Court Decision Required for Proprietary Interest
Note:
A copy in English of a statute or court decision, not from the U.S., relied upon to demonstrate a proprietary interest must be made of record.

A proprietary interest obtained other than by assignment or agreement to assign may be demonstrated by an appropriate legal memorandum to the effect that a court of competent jurisdiction (federal, state, or foreign) would by the weight of authority in that jurisdiction award title of the invention to the pre-AIA 37 CFR 1.47(b) applicant. The facts in support of any conclusion that a court would award title to the pre-AIA 37 CFR 1.47(b) applicant should be made of record by way of an affidavit or declaration of the person having firsthand knowledge of same. The legal memorandum should be prepared and signed by an attorney at law familiar with the law of the jurisdiction involved. A copy (in the English language) of a statute (if other than the United States statute) or a court decision (if other than a reported decision of a federal court or a decision reported in the United States Patents Quarterly) relied on to demonstrate a proprietary interest should be made of record.

Jump to MPEP Source · 37 CFR 1.47(b)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIAPTAB Jurisdiction
Topic

Establishing Ownership

3 rules
StatutoryRequiredAlways
[mpep-409-03-f-e05053845a804ace2f33536c]
Assignment Copy Requirement for Assigned Applications
Note:
If an application has been assigned, a copy of the assignment in English must be submitted.

If the application has been assigned, a copy of the assignment (in the English language) must be submitted. The assignment must clearly indicate that the invention described in the pre-AIA 37 CFR 1.47(b) application was assigned to the pre-AIA 37 CFR 1.47(b) applicant. A statement under pre-AIA 37 CFR 3.73(b) by the assignee must also be submitted (see MPEP § 324). An assignment of an application and any “reissue, division, or continuation of said application” does not itself establish an assignment of a continuation-in-part application. In re Gray, 115 USPQ 80 (Comm’r Pat. 1956). An assignment to a pre-AIA 37 CFR 1.47(b) applicant for the sole purpose of obtaining a filing date for a pre-AIA 37 CFR 1.47(b) application is not considered an assignment within the meaning of pre-AIA 35 U.S.C. 118 and pre-AIA 37 CFR 1.47(b).

Jump to MPEP Source · 37 CFR 1.47(b)Establishing OwnershipWho May File ReissueAssignee as Applicant Signature
StatutoryRequiredAlways
[mpep-409-03-f-13dcc5919d9e76b1c7816c02]
Assignment Statement Requirement for Assignee
Note:
The assignee must submit a statement under pre-AIA 37 CFR 3.73(b) along with the application assignment.

If the application has been assigned, a copy of the assignment (in the English language) must be submitted. The assignment must clearly indicate that the invention described in the pre-AIA 37 CFR 1.47(b) application was assigned to the pre-AIA 37 CFR 1.47(b) applicant. A statement under pre-AIA 37 CFR 3.73(b) by the assignee must also be submitted (see MPEP § 324). An assignment of an application and any “reissue, division, or continuation of said application” does not itself establish an assignment of a continuation-in-part application. In re Gray, 115 USPQ 80 (Comm’r Pat. 1956). An assignment to a pre-AIA 37 CFR 1.47(b) applicant for the sole purpose of obtaining a filing date for a pre-AIA 37 CFR 1.47(b) application is not considered an assignment within the meaning of pre-AIA 35 U.S.C. 118 and pre-AIA 37 CFR 1.47(b).

Jump to MPEP Source · 37 CFR 1.47(b)Establishing OwnershipWho May File ReissueAssignee as Applicant Signature
StatutoryInformativeAlways
[mpep-409-03-f-9072a19d7e0215c3549ca8b5]
Assignment Does Not Include Continuation-In-Part
Note:
An assignment of an application and its reissue, division, or continuation does not automatically include a continuation-in-part application.

If the application has been assigned, a copy of the assignment (in the English language) must be submitted. The assignment must clearly indicate that the invention described in the pre-AIA 37 CFR 1.47(b) application was assigned to the pre-AIA 37 CFR 1.47(b) applicant. A statement under pre-AIA 37 CFR 3.73(b) by the assignee must also be submitted (see MPEP § 324). An assignment of an application and any “reissue, division, or continuation of said application” does not itself establish an assignment of a continuation-in-part application. In re Gray, 115 USPQ 80 (Comm’r Pat. 1956). An assignment to a pre-AIA 37 CFR 1.47(b) applicant for the sole purpose of obtaining a filing date for a pre-AIA 37 CFR 1.47(b) application is not considered an assignment within the meaning of pre-AIA 35 U.S.C. 118 and pre-AIA 37 CFR 1.47(b).

Jump to MPEP Source · 37 CFR 1.47(b)Establishing OwnershipReissue Patent PracticeWho May File Reissue
Topic

AIA vs Pre-AIA Practice

1 rules
StatutoryRecommendedAlways
[mpep-409-03-f-45137c98ab485842ae6718f4]
Assignment Agreement for Pre-AIA Invention
Note:
When an inventor agrees in writing to assign an invention described in a pre-AIA application, a copy of that agreement must be submitted.

When an inventor has agreed in writing to assign an invention described in an application deposited pursuant to pre-AIA 37 CFR 1.47(b), a copy of that agreement should be submitted. If an agreement to assign is dependent on certain specified conditions being met, it must be established by a statement of facts by someone with first hand knowledge of the circumstances in which those conditions have been met. A typical agreement to assign is an employment agreement where an employee (nonsigning inventor) agrees to assign to his or her employer (pre-AIA 37 CFR 1.47(b) applicant) all inventions made during employment. When such an agreement is relied on, it must be established by a statement of a person having firsthand knowledge of the facts that the invention was made by the employee while employed by the pre-AIA 37 CFR 1.47(b) applicant.

Jump to MPEP Source · 37 CFR 1.47(b)AIA vs Pre-AIA PracticeAssignee as Applicant SignatureApplicant and Assignee Filing Under AIA
Topic

PTAB Jurisdiction

1 rules
StatutoryRecommendedAlways
[mpep-409-03-f-2191081faa951705e79a603c]
Legal Memorandum Must Be Signed By Attorney
Note:
A legal memorandum supporting a proprietary interest must be prepared and signed by an attorney familiar with the jurisdiction's law.

A proprietary interest obtained other than by assignment or agreement to assign may be demonstrated by an appropriate legal memorandum to the effect that a court of competent jurisdiction (federal, state, or foreign) would by the weight of authority in that jurisdiction award title of the invention to the pre-AIA 37 CFR 1.47(b) applicant. The facts in support of any conclusion that a court would award title to the pre-AIA 37 CFR 1.47(b) applicant should be made of record by way of an affidavit or declaration of the person having firsthand knowledge of same. The legal memorandum should be prepared and signed by an attorney at law familiar with the law of the jurisdiction involved. A copy (in the English language) of a statute (if other than the United States statute) or a court decision (if other than a reported decision of a federal court or a decision reported in the United States Patents Quarterly) relied on to demonstrate a proprietary interest should be made of record.

Jump to MPEP Source · 37 CFR 1.47(b)PTAB JurisdictionPTAB Contested Case ProceduresAssignee as Applicant Signature
Topic

AIA Effective Dates

1 rules
MPEP GuidanceInformativeAlways
[mpep-409-03-f-62f792fe50292148cc4c7aea]
Rule Not Applicable Post-September 16, 2012
Note:
This rule does not apply to applications filed after September 16, 2012. Instead, refer to MPEP sections 325, 409.05, and 605 for relevant information.

[Editor Note: This MPEP section is not applicable to applications filed on or after September 16, 2012. See MPEP §§ 325, 409.05, and 605 for information pertaining to applications for patent filed on or after September 16, 2012 by an assignee, obligated assignee, or a person who otherwise shows sufficient proprietary interest in the matter.]

Jump to MPEP SourceAIA Effective DatesAIA Overview and Effective DatesAIA vs Pre-AIA Practice

Citations

Primary topicCitation
Assignee as Applicant Signature
Establishing Ownership
35 U.S.C. § 118
AIA vs Pre-AIA Practice
Assignee as Applicant Signature
Establishing Ownership
PTAB Jurisdiction
37 CFR § 1.47(b)
Assignee as Applicant Signature
Establishing Ownership
37 CFR § 3.73(b)
Assignee as Applicant Signature
Establishing Ownership
MPEP § 324
AIA Effective DatesMPEP § 325

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31