This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.
Intervening rights protect third parties who have relied on the original patent claims before the reexamination. As explained in MPEP 2293:
“The doctrine of intervening rights as set forth in 35 U.S.C. 252 protects the substantive rights of persons and businesses that relied on the original text of the patent, prior to reissue or reexamination.”
This protection includes:
- Absolute intervening rights: Allow continued use or sale of specific products made before the reissue or reexamination certificate.
- Equitable intervening rights: May be granted by courts for products made after the reissue or reexamination, based on substantial preparations or investments made before the changes.
These rights ensure that third parties who acted in good faith based on the original patent are not unfairly penalized by changes made during reexamination. It balances the interests of patent holders and those who have relied on the patent’s original scope.