What Is the PTAB? A 2026 Guide for In-House Counsel

The Patent Trial and Appeal Board (PTAB) is the administrative tribunal within the U.S. Patent and Trademark Office that adjudicates contested post-grant patent validity proceedings and ex parte appeals from examiner rejections. Created by the America Invents Act of 2011, Pub. L. No. 112-29, § 7, the Board is an executive-branch administrative tribunal within the USPTO, staffed by Administrative Patent Judges (APJs) sitting in three-judge panels under 35 U.S.C. § 6; the appellate path runs to the U.S. Court of Appeals for the Federal Circuit under 35 U.S.C. § 319 and § 141, with a 63-day filing window under 37 C.F.R. § 90.3.

How the Board Sits Inside the USPTO

The PTAB replaced the Board of Patent Appeals and Interferences in September 2012, when the AIA’s contested-proceedings provisions took effect. Its statutory authority appears at 35 U.S.C. § 6, which provides that the Board “shall consist of the Director, the Deputy Director, the Commissioner for Patents, the Commissioner for Trademarks, and the administrative patent judges.” 35 U.S.C. § 6(a). APJs are appointed by the Secretary of Commerce and decide cases in three-judge panels. Pre-Squires panel-assignment practice was that the same three-judge panel handled both institution and the merits trial; the October 2025 Squires regime changed this for the institution phase only, where the Director now decides whether to institute in consultation with at least three PTAB judges, while the merits panel that handles trial post-institution continues to be a separate three-judge APJ panel.

The Supreme Court resolved the constitutional question in Oil States Energy Services, LLC v. Greene’s Energy Group, LLC, 584 U.S. 325, 337 (2018) (IPR constitutional under Article III + Seventh Amendment), holding that IPR is a permissible exercise of the public-rights doctrine and does not violate Article III or the Seventh Amendment. The Director-appointment question was resolved in United States v. Arthrex, Inc., 594 U.S. 1, 23 (2021) (severability cure — Director Review), where the Court severed the unreviewable-decision aspect of the APJ scheme and required Director review of final written decisions; that severance is now codified at 37 C.F.R. § 42.75.

The Trial Vehicles

In practice, IPR is the predominant trial vehicle. PGR remains rare because of the 9-month window, the broader estoppel scope under § 325(e), and the availability of § 101 and § 112 challenges in district court via Rule 12 motions and summary judgment.

Petition, Preliminary Response, and Institution

A petitioner files an IPR petition meeting the 35 U.S.C. § 312(a) particularity requirements, identifies all real parties in interest, and pays the filing fee. The patent owner has three months from the date of the notice indicating that the petition has been accorded a filing date to file a Patent Owner Preliminary Response (POPR) under 37 C.F.R. § 42.107(b) — note that the clock runs from the notice of accorded filing date, not from the date the petition was first filed. Word-count limits at this stage and throughout trial are governed by 37 C.F.R. § 42.24: the IPR petition (§ 42.24(a)(1)(i)), the POPR (§ 42.24(b)(1)), and the patent owner response (§ 42.24(b)(2)) are each capped at 14,000 words, while the petitioner reply to a patent owner response (§ 42.24(c)(1)) and the sur-reply (§ 42.24(c)(4)) are each capped at 5,600 words.

Under the Squires regime announced October 17, 2025 (clarified October 20, 2025), the Director — in consultation with at least three PTAB judges — decides IPR and PGR institution on a consolidated record at a single phase that addresses both the discretionary-denial framework and the merits in one decision rather than the two-stage bifurcated process used between February and October 2025. The Squires institution regime applies to IPR and PGR; ex parte appeals, derivation proceedings, and the expired CBM program are governed by their own pre-existing procedures. This regime succeeds two prior phases: the June 21, 2022 Vidal memo (which constrained Fintiv-based discretionary denials) was rescinded on February 28, 2025; the March 26, 2025 Interim Processes for PTAB Workload Management memorandum, authored by Acting Director Coke Morgan Stewart, then established a bifurcated discretionary-vs-merits process; and the Squires memo replaced that bifurcation in October 2025. On March 11, 2026, the USPTO added three further discretionary considerations: petitioner U.S. manufacturing investment, patent-owner U.S. manufacturing footprint, and small-business petitioner status.

The substantive discretionary framework remains Apple Inc. v. Fintiv, Inc., IPR2020-00019 (precedential — six-factor discretionary-denial framework), with Sotera Wireless, Inc. v. Masimo Corp., IPR2020-01019 (precedential as to § II.A — stipulation as a strong factor against discretionary denial) recognized as a meaningful factor under Fintiv factor 4. After the February 28, 2025 rescission of the 2022 Vidal memo, however, a Sotera-style stipulation is no longer a categorical safe harbor or pathway around Fintiv denial — it remains a weighty consideration but the bright-line shall-not-deny treatment is gone. Under § 314(a), the Director may decline to institute even where the petition shows a reasonable likelihood of prevailing on at least one challenged claim.

The One-Year Bar, the Civil-Action Bar, and Joinder

Two § 315 bars govern when an IPR can be filed at all. Under 35 U.S.C. § 315(b), an IPR petition is barred if filed more than one year after the petitioner, real party in interest, or privy is served with a complaint alleging infringement. The Federal Circuit clarified in Click-to-Call Technologies, LP v. Ingenio, Inc., 899 F.3d 1321 (Fed. Cir. 2018) (panel; en banc agreement on voluntary-dismissal rule in fn 3) that voluntary dismissal of the underlying district-court suit without prejudice does not reset the § 315(b) clock; that aspect of Click-to-Call survives even though the Supreme Court vacated and remanded with instructions to dismiss in Thryv, Inc. v. Click-to-Call Technologies, LP, 590 U.S. 45 (2020) (§ 314(d) precludes appellate review of § 315(b) timeliness determinations — statutory non-reviewability, not Article III jurisdictional vacatur). The footnote-3 holding on the voluntary-dismissal rule was a 10-2 vote, with Judges Dyk and Lourie dissenting and Judge Taranto concurring separately — not a unanimous en banc panel.

§ 315(a)(1) imposes a separate, often-overlooked bar: an IPR petition is barred if the petitioner has previously filed a civil action challenging the validity of any claim of the patent. The classic trap is filing a declaratory-judgment action and then trying to file an IPR; the DJ filing forecloses the IPR even though counterclaims of invalidity in a defensive posture do not. § 315(a)(2) further provides that an IPR filed before any subsequent DJ challenge by the petitioner stays the DJ action.

For joinder, § 315(c) is read narrowly. Facebook, Inc. v. Windy City Innovations, LLC, 973 F.3d 1321, 1336 (Fed. Cir. 2020) (limiting the joinder provision to different-party, same-issue joinder), held that § 315(c) authorizes joinder only of a different party to an existing IPR on the same issues — it does not authorize same-party “issue joinder” that would let a petitioner add new claims or grounds to its own pending IPR after the § 315(b) clock has run. The procedural timing rule for joinder motions appears at 37 C.F.R. § 42.122(b): a motion for joinder must be filed no later than one month after institution of the proceeding to be joined.

The Trial: Discovery, Motions, and Final Written Decision

After institution, the proceeding moves to a one-year statutory trial under 35 U.S.C. § 316(a)(11), which requires the final written decision to issue within one year of institution, extendable for up to six months for good cause. In the typical schedule, the patent owner’s response and any motion to amend under § 316(d) are due roughly three months after institution; petitioner’s reply roughly three months later; sur-reply, oral hearing, and final written decision follow within the statutory window.

Discovery is limited and scoped under 37 C.F.R. § 42.51: mandatory initial disclosures, routine discovery (cross-examination of declarants, inconsistent statements, information cited in papers), and additional discovery only on a showing of “interests of justice” — 37 C.F.R. § 42.51(b)(2) — under Garmin Int’l, Inc. v. Cuozzo Speed Techs. LLC, IPR2012-00001 (precedential as to discovery factors).

Claim construction at the PTAB follows the Phillips standard. The November 13, 2018 amendments to 37 C.F.R. § 42.100(b) replaced the broadest-reasonable-interpretation standard with the Phillips v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc) framework — the same standard a federal district court applies under Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996) (claim construction is question of law). On Federal Circuit appellate review, claim construction’s ultimate legal conclusions receive de novo review. PTAB factual findings — including subsidiary fact-findings on extrinsic evidence — are reviewed for substantial evidence under the Administrative Procedure Act, 5 U.S.C. § 706(2)(E), per Dickinson v. Zurko, 527 U.S. 150 (1999) (APA substantial-evidence review of PTO factual findings), and Knowles Electronics LLC v. Cirrus Logic, Inc., 883 F.3d 1358, 1362 (Fed. Cir. 2018) (substantial-evidence standard for PTAB fact-findings). Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., 574 U.S. 318, 332 (2015) (modifying Cybor — FRCP 52(a)(6) clear-error review for district-court fact-findings on extrinsic evidence) applies by analogy for the deference owed to subsidiary fact-findings in district-court appeals, but the operative PTAB-appeal standard remains substantial evidence, not clear error; the Federal Circuit modified Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc), in the district-court appellate context only.

Motion to Amend

Under § 316(d) and 37 C.F.R. § 42.121, the patent owner may move to amend by canceling claims or proposing reasonable substitute claims. The MTA framework evolved in three distinct stages: (1) the USPTO launched the Motion to Amend Pilot Program in March 2019 (84 Fed. Reg. 9497), creating optional procedural mechanisms (preliminary guidance and revised MTAs) without first codifying burden allocation; (2) the December 21, 2020 final rule (85 Fed. Reg. 82923, 82936, effective January 21, 2021) separately codified the burden of persuasion at 37 C.F.R. § 42.121(d) and § 42.221(d), placing the burden on the petitioner to prove unpatentability of the substitute claims by a preponderance — that 2020 rule did NOT implement the pilot; and (3) the September 18, 2024 final rule made the pilot procedural mechanisms permanent and added new subsections governing preliminary guidance and revised motions. The legal foundation comes from Aqua Products, Inc. v. Matal, 872 F.3d 1290 (Fed. Cir. 2017) (en banc plurality — fragmented decision signaling that the patent owner should not bear the burden on patentability of substitute claims), which the USPTO subsequently codified through the 2020 rulemaking.

Final Written Decision and SAS

The final written decision must address all challenged claims and all grounds raised in the petition. SAS Institute Inc. v. Iancu, 138 S. Ct. 1348, 1359–60 (2018) (no partial institution — all challenged claims and grounds), held that § 318(a) requires the Board to address every claim challenged in the petition once it institutes — partial institution is not permitted, and the regime is all challenged claims AND all grounds. The Office’s post-SAS guidance confirms that institution is on all grounds in the petition or no grounds at all.

Estoppel and the Caltech Lineage

35 U.S.C. § 315(e) bars a petitioner from later asserting in district court or the ITC any ground that it “raised or reasonably could have raised” — 35 U.S.C. § 315(e)(2) — in an IPR that reached final written decision. The scope of that estoppel evolved through three Federal Circuit decisions:

The interaction between the PTAB’s preponderance standard and the Microsoft Corp. v. i4i framework (establishing the clear-and-convincing evidence standard for invalidity defenses raised in district-court litigation) is the strategic heart of IPR practice. At the PTAB, validity is decided by preponderance of the evidence under § 316(e). In district court, an issued patent enjoys the presumption of validity under 35 U.S.C. § 282, and an accused infringer must overcome it by clear and convincing evidence per Microsoft Corp. v. i4i, 564 U.S. at 95 (clear-and-convincing evidence standard for invalidity). Because of that asymmetry, accused infringers often prefer the PTAB on art they can win on; once the final written decision issues, the § 315(e) estoppel triggers for any ground that the petitioner “raised or reasonably could have raised” under 35 U.S.C. § 315(e)(2).

Settlement, Termination, and the Director’s Discretion

Under 35 U.S.C. § 317, parties may file a joint settlement and request termination of the IPR. The Board may terminate the proceeding as to the settling parties and continue against any non-settling petitioners. Where settlement comes before institution, termination is the default; post-institution, the Board has discretion to issue a final written decision on the merits notwithstanding settlement, particularly where the record is closed. A settlement agreement filed under § 317(b) is treated as business confidential information and “shall be kept separate from the file of the involved patents,” 35 U.S.C. § 317(b), available only to Federal Government agencies on written request, or to any other person on a showing of good cause.

Director Review

After Arthrex, the Director has authority to review final written decisions sua sponte or on a party request. The current rule is at 37 C.F.R. § 42.75, as amended by the final rule at 89 Fed. Reg. 79744, 79751 (Oct. 1, 2024), which formalized the Director Review process the Office had typically operated by interim procedure since 2021. Director Review is discretionary and is granted in only a small fraction of cases; rehearing under 37 C.F.R. § 42.71 is the more commonly used mechanism for procedural error or overlooked argument.

Federal Circuit Appeal

A party adverse to a final written decision may appeal to the Federal Circuit under 35 U.S.C. § 319 and 28 U.S.C. § 1295(a)(4)(A) — the exclusive appellate path, though appeal itself is optional. The notice of appeal is filed within 63 days of the final written decision under 37 C.F.R. § 90.3(a)(1); when timely rehearing is sought, § 90.3(b)(1) resets the clock to 63 days after action on the rehearing request. Extensions are governed by § 90.3(c)(1), which requires good cause (pre-expiration) or excusable neglect (post-expiration). Institution decisions remain non-appealable under 35 U.S.C. § 314(d), as construed in Cuozzo Speed Technologies, LLC v. Lee, 579 U.S. 261, 273 (2016) (sustaining the statutory bar on judicial review of institution decisions), and reaffirmed in Thryv.

The standard of review at the Federal Circuit follows the usual administrative-law pattern: legal conclusions are reviewed de novo, factual findings under the Administrative Procedure Act’s substantial-evidence test, and discretionary determinations for abuse of discretion. Standing to appeal a PTAB loss is itself a threshold question — see Phigenix and JTEKT, above.

Procedural Recap — Key Clocks at a Glance

Frequently Asked Questions