USPTO Issues Revised Guidance for AI-Assisted Inventions: Pannu Factors No Longer Apply to Single-Inventor Cases

In 2025, the U.S. Patent and Trademark Office (USPTO) issued the Revised Inventorship Guidance for AI-Assisted Inventions (the “2025 Guidance ^[1] ”), expressly rescinding and replacing the prior guidance issued on February 13, 2024 (the “2024 Guidance ^[2] ”).

The most significant change in the 2025 Guidance is the clarification and narrowing of when the Pannu factors apply. The Pannu factors are used to determine whether, among multiple natural persons, each qualifies as a joint inventor by making a significant contribution to the invention. In general, a named inventor must satisfy all three Pannu factors:

1. Contribute in some significant manner to the conception or reduction to practice of the invention;

2. Make a contribution to the claimed invention that is not insignificant in quality, when that contribution is measured against the dimension of the full invention; and

3. Do more than merely explain to the real inventors well-known concepts and/or the current state of the art ^[3] .

Under the 2024 Guidance, the USPTO suggested that even where only one natural person used AI to assist in the significant contribution to the invention, inventorship should still be assessed using the Pannu factors ^[4] . The 2025 Guidance expressly rejects this approach.

The USPTO clarifies that the Pannu factors are legally relevant only in cases involving multiple natural persons. Because AI systems are not natural persons and cannot be inventors or joint inventors, there is no basis to apply the Pannu factors where a single natural person invents with the assistance of AI ^[5] .
Based on this clarification, the USPTO sets out the following framework:

1. Single natural person using AI
Where one natural person creates an invention with AI assistance, inventorship should be determined under the “Conception” standard. The Federal Circuit has consistently treated the “Conception” standard as the touchstone of inventorship when determining whether a particular individual qualifies as an inventor. Under the conception standard, an inventor must have formed in their mind a definite and permanent idea of the complete and operative invention, meaning that the invention is clearly defined and its practical implementation is fully understood. Conception is deemed complete when the inventor has developed a specific and settled solution to the problem, as opposed to articulating only a general goal or abstract research plan ^[6] .

2. Multiple natural persons using AI
Only where multiple natural persons are involved does the Pannu analysis apply, to determine whether joint inventorship exists.

Overall, the 2025 Revised Guidance reaffirms that AI is treated as a tool under patent law, analogous to laboratory equipment, computer software, or research databases, rather than as an inventor. The Guidance further clarifies the proper scope of the Pannu factors, expressly stating that they should not be applied in cases involving a single natural person who invents with the assistance of AI. In such cases, inventorship should instead be assessed under the traditional “Conception” standard.

[1]  Revised Inventorship Guidance for AI-Assisted Inventions(U.S. Pat. & Trademark Off., Nov. 28, 2025),
https://www.federalregister.gov/documents/2025/11/28/2025-21457/revised-inventorship-guidance-for-ai-assisted-inventions.
[2] Inventorship Guidance for AI-Assisted Inventions, 89 Fed. Reg. 10043 (Feb. 13, 2024).
[3] Pannu v. Iolab Corp., 155 F.3d 1344, 1351 (Fed. Cir. 1998).
[4] Inventorship Guidance, supra note 2, at 10054.
[5] Revised Inventorship Guidance, supra note 1.
[6] Burroughs Wellcome Co. v. Barr Labs., Inc., 40F.3d 1223, 1228 (Fed. Cir. 1994). (“The Federal Circuit has centered its inventorship inquiry around ‘conception,’ characterizing conception as ‘the touchstone of inventorship.’”)