IPR Filings Hit Historic Low as Ex Parte Reexamination Eclipses Inter Partes Review for First Time Since AIA

Inter partes review (IPR) petitions filed at the U.S. Patent and Trademark Office have fallen to a level not seen since the system launched in September 2012. For the four-week period ending May 2, 2026, only eleven IPR petitions were filed — a figure that stands in stark contrast to the stable band of roughly 80 to 130 filings per 28-day window that characterized the period from 2021 through mid-2025. The collapse tracks directly to the expanded discretionary-denial policy pursued by USPTO Director John Squires since his confirmation in fall 2025.

The shift has produced a structural inversion that IP practitioners are calling unprecedented: for the first time since the America Invents Act (AIA) brought IPR into existence, ex parte reexamination requests have overtaken IPR petitions as the leading post-grant patent validity tool at the initial petition stage. In Q1 2026, IPR petitions dropped 66.3% year-over-year while ex parte reexamination requests surged 157.1% over the same period, according to data compiled by Patently-O (published May 2, 2026). Ex parte reexamination requests, which had quietly remained between 20 and 40 per 28-day window for years, now peak above 130 — the majority being third-party requests rather than patentee-initiated ones.

The Squires Effect

The decline in IPR petitions developed in two phases. A gradual softening began under Acting Director Coke Morgan Stewart in the first half of 2025. When Director Squires assumed office in late 2025, the rate of institution accelerated downward toward what analysts are calling a single-digit floor. Squires has pursued a Director-centric model at the Patent Trial and Appeal Board (PTAB), consolidating IPR institution authority and exercising broad discretionary denial across virtually all petitions. For prospective IPR petitioners, who face petition filing fees alone in the tens of thousands of dollars, the risk of total non-institution converts the exercise into an unrecoverable sunk cost.

Why Ex Parte Reexamination Wins Under the New Regime

Two structural features make ex parte reexamination an attractive alternative. The first is estoppel. Under 35 U.S.C. § 315(e), any party that proceeds through an IPR to a final written decision is statutorily barred from raising in district court any invalidity ground it reasonably could have raised during the review. No comparable estoppel attaches to ex parte reexamination — a challenger that loses a reexamination proceeding retains its ability to assert invalidity in litigation. For defendants in patent suits who want to preserve maximum optionality while simultaneously pressing on validity at the USPTO, the estoppel calculus strongly favors reexamination.

The second advantage is anonymity. Third parties may file ex parte reexamination requests without disclosing their identity, allowing the real party in interest to remain concealed. The USPTO updated its guidance on February 6, 2026 to address potential abuse: where a patent has already been the subject of an IPR or post-grant review (PGR) that produced a final written decision on at least one claim, an anonymous requester must now include an affirmative certification that the real party in interest is neither the prior IPR/PGR petitioner nor a privy thereof. The change is designed to prevent defeated IPR petitioners from using an anonymous reexamination filing as a second bite at the apple.

New Pre-Order Procedure for Patent Owners

Responding to the surge in reexamination requests, the USPTO published an Official Gazette Notice on April 1, 2026 establishing a new pre-order paper procedure, effective for requests filed on or after April 5, 2026. Patent owners now have a formal opportunity — before the USPTO determines whether to order reexamination — to submit a paper of up to 30 pages arguing that the cited prior art references do not raise a substantial new question of patentability (SNQ). The paper requires no petition or fee and must be filed within 30 days of service of the reexamination request. If the USPTO agrees, reexamination is never ordered and the patent owner avoids the full procedural burden of defending through the reexamination proceeding.

Implications for Patent Strategy

The structural inversion reshapes the patent invalidity toolkit on both sides. Defendants and accused infringers accustomed to reaching for IPR as a first-line defense must now assess whether the reexamination route better preserves their litigation optionality, recognizing that an unfavorable reexamination outcome does not foreclose invalidity arguments at trial. Patent owners, particularly non-practicing entities, face a modestly lower post-grant validity threat from PTAB proceedings, but cannot count on director-level discretionary denial to insulate their portfolios from all challengers — reexamination remains a live weapon. The durability of the Squires policy, and whether Congress will intervene legislatively to reassert IPR as a meaningful check on patent validity, is expected to be a defining issue for U.S. patent practice throughout 2026.