The Rise of Ex Parte Reexamination Over the IPR

This falloff is widely attributed to the decrease in institutions following significant policy changes last year, including the removal of guidelines for discretionary denials of IPR petitions. Prior to the policy changes, IPR petitions were instituted about 66% of the time. That number dropped to 50% in 2025. This year, the number of instituted IPR petitions is on course to drop below the 50% mark. The precipitous drop in institution decisions has forced litigants to look elsewhere, and a new leader has emerged: ex parte reexamination. Ex parte reexaminations have exploded in popularity, with requests increasing from around 100 per quarter in 2025 to over 250 in the first quarter of 2026. 

Ex parte reexamination offers advantages over IPRs in the new landscape. First, unlike IPRs, ex parte reexaminations have a 95% acceptance rate. The process includes submitting a request that presents a “substantial new question of patentability.” The request is granted if it meets the lower standard that a reasonable examiner would consider the prior art to be “important” on the question of patentability (compared to the “substantial new question of patentability” standard for IPRs). Second, there is no risk of estoppel with reexamination. Because the requesting party does not participate in the reexamination, there are no arguments made regarding invalidity that could lead to estoppel. Third, there are no time constraints for reexamination. An IPR petition, by contrast, must be filed within one year of service of a complaint for patent infringement. A reexamination request has no such constraints. And fourth, ex parte reexaminations are significantly less expensive than IPRs.

Taken as a whole, ex parte reexamination is a popular alternative to IPRs due to the rise in discretionary denials. 

We are monitoring this situation closely as it continues to develop and will provide updates as they are available.