---
kind: "section"
citation: "37 C.F.R. § 42.201"
title: "37"
number: "42.201"
heading: "Who may petition for a post-grant review."
url: "https://uscodex.org/cfr/37/42.201"
---

# §42.201. Who may petition for a post-grant review.


A person who is not the owner of a patent may file with the Office a petition to institute a post-grant review of the patent unless:

- (a) Before the date on which the petition for review is filed, the petitioner or real party-in-interest filed a civil action challenging the validity of a claim of the patent; or
- (b) The petitioner, the petitioner's real party-in-interest, or a privy of the petitioner is estopped from challenging the claims on the grounds identified in the petition.

## Notes

### Source

Source: 77 FR 48729, Aug. 14, 2012, unless otherwise noted.

### Authority

Authority: 35 U.S.C. 2(b)(2), 3, 6, 21, 23, 41, 134, 135, 143, 153, 311, 312, 314, 316, 318, 321-326, 328; Pub. L. 112-29, 125 Stat. 284; and Pub. L. 112-274, 126 Stat. 2456.

### Source

Source: 77 FR 48669, Aug. 14, 2012, unless otherwise noted.