Who may petition for inter partes review.

§ 42.101 Who may petition for inter partes review. A person who is not the owner of a patent may file with the Office a petition to institute an inter partes 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; (b) The petition requesting the proceeding is filed more than one year after the date on which the petitioner, the petitioner's real party-in-interest, or a privy of the petitioner is served with a complaint alleging infringement of the patent; or (c) 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.