Who Can Use Inter Partes Review?
Ever since its introduction in 2012 with the enactment of the America Invents Act, Inter Partes Review (IPR) petitions have been a popular alternative, or tangential…
[SERVICE]Post-grant proceedings
Post-grant proceedings to challenge or defend a patent
An issued patent can be challenged or defended at the USPTO without a lawsuit. We handle PTAB proceedings and reexaminations for challengers and patent owners, with fees quoted after a review.
Your attorneys
Andrew RapackeManaging Partner · Registered Patent AttorneyElectrical and computer engineering. Former Naval Engineering Officer.
[01]Who it's for
For anyone on either side of an issued patent.
Most post-grant work starts with a patent that is in the way, or a patent someone else wants out of the way. The proceeding you choose, and when you file it, decides what you can argue.
Companies accused of infringement
A petition at the USPTO can challenge the patent while the lawsuit runs, if it is filed within one year of being served.
Companies clearing a launch
A patent that blocks your product can be challenged before you ship, not after a demand letter arrives.
Patent owners facing a petition
A preliminary response, a trial defense and, where it helps, narrower claims that hold up.
Competitors watching new grants
In the first nine months after a patent issues, post-grant review allows the widest range of challenges.
[02]What it can do
What a post-grant proceeding can and cannot do.
These proceedings decide one question, whether the claims of an issued patent should have been granted. They are faster and more technical than a court case, and narrower.
Which proceeding fits depends on when the patent issued, what evidence you have and whether you have been sued. Your attorney walks through it on the first call.
What it can do
- Cancel claims over prior artIPR and ex parte reexamination can cancel claims that were not new or were obvious in light of earlier patents and publications.
- Cancel claims on any invalidity groundWithin nine months of grant, post-grant review can also reach eligibility, written description, enablement and definiteness.
- Narrow the claimsA patent owner can propose narrower substitute claims instead of losing a claim outright.
- Run alongside a lawsuitA petition can proceed while an infringement case is pending, and courts can stay the case to wait for the result.
What it cannot do
- Decide infringementWhether a product infringes is a question for a court, not the PTAB.
- Award damages or an injunctionOnly a court can order money or stop sales.
- Use public use or sales in an IPRIPR and reexamination rely on patents and printed publications only. Public use and on-sale evidence belong in post-grant review or court.
- Broaden a claimAmendments in any of these proceedings can narrow claims, never enlarge them.
- Guarantee a trialThe USPTO Director decides whether to institute, and a denial cannot be appealed.
[03]Your options
IPR vs post-grant review vs ex parte reexamination.
Three ways to ask the USPTO to take a second look at an issued patent. They differ in who can file, when, on what grounds and what it costs to lose.
| Inter partes review (IPR) | Post-grant review (PGR) | Ex parte reexamination | |
|---|---|---|---|
| Who can file | Anyone except the patent owner | Anyone except the patent owner | Anyone, including the patent owner |
| When | After the nine-month PGR window closes. Barred more than one year after you are served with an infringement complaint | Within nine months of grant or reissue, for patents with a claim filed on or after March 16, 2013 | Any time while the patent is enforceable |
| Grounds | Novelty and obviousness only | Any invalidity ground, including eligibility, written description, enablement and definiteness | Novelty and obviousness only |
| Evidence | Prior patents and printed publications, with declarations from technical witnesses | Any evidence, including public use and sales | Prior patents and printed publications |
| Threshold to start | A reasonable likelihood of winning on at least one claim | More likely than not that at least one claim is unpatentable, or a novel legal question important to other patents | A substantial new question of patentability |
| Who decides | The USPTO Director decides whether to institute. A panel of at least three PTAB judges runs the trial | The USPTO Director decides whether to institute. A panel of at least three PTAB judges runs the trial | An examiner in the USPTO's Central Reexamination Unit |
| The challenger's role | A full party through trial, hearing and appeal | A full party through trial, hearing and appeal | Files the request and may reply once to the owner's statement, then steps out |
| How claims are read | Their ordinary meaning, as a court would read them | Their ordinary meaning, as a court would read them | Their broadest reasonable interpretation |
| Time to a decision | Final written decision within one year of institution, extendable by six months | Final written decision within one year of institution, extendable by six months | Order within three months of the request. No fixed deadline after that |
| Estoppel for the challenger | Yes, on any ground raised or that reasonably could have been raised | Yes, and it reaches further because any ground could have been raised | None in the reexamination statute |
| USPTO fees, up to 20 claims | $23,750 to request plus $28,125 if instituted | $25,000 to request plus $34,375 if instituted | $13,545, or $5,418 for a small entity and $2,709 for a micro entity |
| Statute | 35 U.S.C. 311 to 319 | 35 U.S.C. 321 to 329 | 35 U.S.C. 302 to 307 |
USPTO fees are from the USPTO fee schedule, last revised August 14, 2026. IPR and PGR fees have no small or micro entity discount. Our fee is separate and is quoted after a review of the patent and the record.
[04]Post-grant review
What is post-grant review?
Post-grant review is a trial at the Patent Trial and Appeal Board that can cancel claims of a newly issued patent on almost any invalidity ground. It has to be filed within nine months of the patent's grant or reissue.
The nine-month window
The petition must be filed no later than nine months after the patent is granted, or after a reissue patent issues. After that, the same patent can only be challenged at the USPTO through inter partes review or ex parte reexamination, on prior art grounds. If a competitor's patent matters to you, watch for it to issue.
Which patents it applies to
Post-grant review applies to patents examined under the first-inventor-to-file rules, which generally means a patent with at least one claim with an effective filing date on or after March 16, 2013.
What can be argued
Any ground that could be raised in court as invalidity under the conditions for patentability or the disclosure requirements. That includes lack of novelty or obviousness on any kind of prior art, including public use and sales, plus patent eligibility, written description, enablement and indefiniteness.
The bar to start
The petition has to show that it is more likely than not that at least one challenged claim is unpatentable, or raise a novel or unsettled legal question that matters to other patents. That is a higher bar than inter partes review.
The tradeoff
Because almost any ground can be raised, almost any ground is lost if it is not. After a final written decision, the petitioner cannot later argue in court or at the USPTO that a claim is invalid on any ground it raised or reasonably could have raised.
[05]Inter partes review
Inter partes review, in brief.
Inter partes review is the PTAB trial used to challenge an issued patent on prior art. It is limited to novelty and obviousness, argued on prior patents and printed publications.
Congress created it in the America Invents Act, replacing the older inter partes reexamination, and it has applied since September 16, 2012 to patents issued before or after that date. A petition can be filed once nine months have passed since grant, or once an instituted post-grant review has ended.
The petition has to name every real party in interest, identify each challenged claim and the grounds, and attach the prior art and any witness declarations it relies on. For who can bring one and when it makes sense, see who can use inter partes review and is IPR a better option than fighting for invalidation in court. More on the deadlines in time restrictions on starting an inter partes review.
[06]Reexamination
How ex parte reexamination works.
Ex parte reexamination asks a USPTO examiner to look at an issued patent again in light of prior patents or publications. Anyone can request it, at any time while the patent is enforceable, including the patent owner.
The request
The request explains how each cited patent or publication applies to every claim it challenges. Within three months, the USPTO decides whether it raises a substantial new question of patentability. Art the examiner already saw can still raise one.
After the order
The patent owner may file a statement, including amendments, and the requester may reply once. From there the examination runs between the examiner and the patent owner, much like the original prosecution, and the requester takes no further part. The owner can amend or add claims but cannot broaden them, and can appeal an adverse decision.
When it fits
Reexamination costs less in USPTO fees than a PTAB trial and carries no statutory estoppel of its own, but the challenger gives up control once it is filed. Patent owners use it too, to have the office consider prior art they have learned about and come out with confirmed or amended claims.
[07]How we work
On the challenger's side or the patent owner's.
We handle PTAB proceedings for both sides. The work starts the same way, with a close read of the patent, its prosecution history and the prior art, then a plain recommendation on whether a proceeding makes sense and which one.
If you are challenging a patent
- Pick the proceeding that fits the timing, the evidence and any lawsuit
- Search for the strongest prior art, not only the art you already have
- Prepare the petition and the technical declaration behind it
- Brief the discretionary issues the Director weighs
- Coordinate with patent litigation counsel if you have been sued
If your patent is being challenged
- Decide whether to file a preliminary response, and what it should argue
- Answer the discretionary issues before institution
- Defend the claims at trial, with your own technical witness where it helps
- Propose narrower substitute claims where that keeps the patent valuable
- Consider tools owners can start themselves, like supplemental examination or reexamination
What to bring to your first call
- The patent number, and any related patents in the family
- Any complaint, demand letter or license offer, with the date you were served or received it
- Prior art you know of, including products sold before the filing date
- Your product or the accused product, and what it does
- Any deadlines you are working to
The fee for a post-grant proceeding is quoted after a review of the patent and the record, before any work begins. For trademarks, the counterpart is TTAB opposition and cancellation.
[08]The PTAB timeline
How long does an IPR or post-grant review take?
About a year and a half from petition to final written decision is typical, because the statute sets most of the clock. Appeals add time after that.
| Stage | Timing | What happens |
|---|---|---|
| Petition filed | Day 0 | The petition, prior art and witness declarations. The USPTO then accords a filing date |
| Patent owner preliminary response | Up to 3 months after the filing date notice | The owner explains why no trial should be instituted, or waives the response |
| Institution decision | Within 3 months of the preliminary response | The Director grants or denies a trial. A denial cannot be appealed |
| Trial | About 12 months | Patent owner response and any motion to amend, petitioner reply, depositions of declarants, oral hearing |
| Final written decision | Within 1 year of institution, extendable by 6 months | The Board decides patentability of each challenged claim |
| Director Review and appeal | After the decision | A party may request Director Review, then appeal to the Federal Circuit |
Who decides whether a trial starts
Since October 20, 2025, the USPTO Director decides whether to institute every IPR and post-grant review, in consultation with at least three PTAB judges, usually by a short notice. Under a process in place since March 2025, the parties can also file briefs on discretionary reasons to deny, such as a parallel lawsuit. In 2026 the Director added factors on US manufacturing and on small businesses that have been sued. A strong petition on the merits can still be denied, so the discretionary record matters from day one.
Rules still in motion
In October 2025 the USPTO proposed rules that would bar IPR in more situations, such as when the same claims were already upheld in another forum. As of October 2026 they had not been published as a final rule. We check the current rules before any petition or response is filed.
[09]Estoppel
What is IPR estoppel, and why does it matter?
Estoppel is the price of losing at the PTAB. After a final written decision, the petitioner cannot reargue the same claim on grounds it raised or reasonably could have raised.
It applies to the petitioner, the real party in interest and anyone in privity with them. It reaches later USPTO proceedings, district court cases and the International Trade Commission. In post-grant review the same rule covers any invalidity ground, so the estoppel is broader.
Estoppel only attaches when the trial reaches a final written decision. If the parties settle and the review is terminated for the petitioner before the Board decides the merits, no estoppel attaches to that petitioner, though the Board may still proceed to a decision. Any settlement agreement has to be filed with the USPTO.
[10]The flat-fee path
One fee, quoted after a review.
Every post-grant matter is different, so we read the patent and the record first, then quote the fee before any work begins. USPTO fees are separate and listed below.
01Start here
Post-grant proceeding
Quoted
After a review of the patent and the record
- A review of the patent, its prosecution history and the prior art
- A recommendation on which proceeding fits, if any
- A fee quoted before any work begins
Before any work begins
Not covered by the guarantee
Post-grant proceedings are quoted after a review of the patent and the record, and are not covered by the guarantee. How The RLG Guarantee works
[11]The process
From first call to final written decision.
The steps for an IPR or post-grant review, from either side. Timing shown is typical or set by statute, never a promised date.
PTAB trialReview to decision
- Day one01Day oneStrategy callWalk your attorney through the patent and the dispute.
- Before any work02Before any workRecord reviewThe patent, its file history and the prior art. Then a quote.
- Up to 3 months03Up to 3 monthsPetition or responseThe petition, or the owner's preliminary response.
- About 3 months later04About 3 months laterInstitution decisionThe Director grants or denies a trial.
- PTAB05PTABTrialResponses, any motion to amend, depositions, oral hearing.
- About month 1806About month 18Final written decisionWithin a year of institution, extendable by six months.
- 07Review or appealDirector Review, then the Federal Circuit.
[12]Other proceedings
Derivation proceedings and covered business method review.
Two more PTAB proceedings from the America Invents Act. One is still available, and one is closed to new petitions.
Derivation proceedings
A derivation proceeding decides whether an inventor named in an earlier application took the invention from an inventor named in yours and filed without authorization. The petition has to set out the basis with particularity, and it must be filed within one year of the earlier of the date the patent with the claim was granted or the application with the claim was published. The Board can correct who is named as inventor.
Covered business method review
This transitional program let parties sued or charged with infringement of certain business method patents challenge them under post-grant review procedures. It closed to new petitions on September 16, 2020. Proceedings filed before that date continued under the old rules.
[13]What it costs
What does a post-grant proceeding cost?
Two parts. The USPTO's fees, which are fixed and public, and our fee, which is quoted after a review of the patent and the record. You know both before any work begins.
| Item | Who sets it | Amount |
|---|---|---|
| Our fee | Rapacke Law Group | Quoted after a review of the patent and the record |
| IPR request fee, up to 20 claims | USPTO | $23,750, plus $470 for each claim over 20 |
| IPR post-institution fee, up to 20 claims | USPTO | $28,125, plus $940 for each claim over 20 |
| PGR request fee, up to 20 claims | USPTO | $25,000, plus $595 for each claim over 20 |
| PGR post-institution fee, up to 20 claims | USPTO | $34,375, plus $1,315 for each claim over 20 |
| Ex parte reexamination request | USPTO | $13,545, or $5,418 for a small entity and $2,709 for a micro entity |
USPTO fees are from the USPTO fee schedule, last revised August 14, 2026. IPR and PGR fees are the same for every entity size, and the post-institution fee is due only if a trial is instituted. A petition usually relies on a declaration from a technical witness, whose fees are separate. For a fuller picture, see why IPR can be expensive but worth it.
[14]Questions
Questions about post-grant proceedings.
Facing a patent, or defending one? Your first call is free and comes with a straight answer on your options.
Book A Free Strategy CallWhat are post-grant proceedings?
They are USPTO proceedings that review whether an issued patent's claims should have been granted. The main ones are inter partes review and post-grant review, which are trials at the Patent Trial and Appeal Board, and ex parte reexamination, which is handled by an examiner. Each can cancel claims, and the owner can narrow claims to keep them.
What is the difference between IPR and post-grant review?
Timing and scope. Post-grant review must be filed within nine months of grant and can raise almost any invalidity ground. Inter partes review is available after that window and is limited to novelty and obviousness based on prior patents and printed publications. Post-grant review also has a higher bar to start and a broader estoppel.
How long does a post-grant proceeding take?
For IPR and post-grant review, about a year and a half from petition to final written decision is typical. The institution decision comes within three months of the owner's preliminary response, and the Board must decide within one year of instituting, extendable by six months. Ex parte reexamination has no fixed end date.
How much does a post-grant proceeding cost?
Our fee is quoted after a review of the patent and the record, before any work begins. USPTO fees are separate. For up to 20 claims, an IPR costs $23,750 to request and $28,125 more if instituted, and a post-grant review costs $25,000 and $34,375. An ex parte reexamination request is $13,545, less for small and micro entities.
I have been sued for patent infringement. Can I still file an IPR?
Yes, if you file within one year of being served with the complaint. After that, the petition is barred unless it joins a review that has already been instituted. Post-grant review and ex parte reexamination have no such bar, but post-grant review is only open for nine months after grant.
What happens if the PTAB denies my petition?
The decision whether to institute is final and cannot be appealed. No estoppel attaches, because there is no final written decision, so the invalidity arguments remain available in court or in an ex parte reexamination request.
Can the patent owner change the claims during the proceeding?
Yes, within limits. In IPR and post-grant review the owner can file one motion to cancel claims or propose a reasonable number of narrower substitute claims. In reexamination the owner can amend or add claims. No proceeding allows a claim to be broadened.
What is estoppel in an IPR?
After a final written decision, the petitioner and those connected to it cannot argue in court, at the ITC or at the USPTO that a claim is invalid on any ground they raised or reasonably could have raised in the IPR. It is why the prior art search is done before the petition is filed.
Can a patent owner use these proceedings?
Yes. A patent owner can request ex parte reexamination of its own patent, or supplemental examination to have the office consider, reconsider or correct information. Both can end with claims confirmed or amended. Owners cannot file an IPR or post-grant review against their own patent.
Is IPR better than challenging a patent in court?
It depends on the case. A PTAB trial is decided by technically trained judges, usually in a fixed time, and the challenger only has to prove unpatentability by a preponderance of the evidence. But it is limited to prior patents and publications, and estoppel can narrow your court defenses. We weigh both on your first call.
What happens after the final written decision?
Either side can request Director Review and then appeal to the Court of Appeals for the Federal Circuit. When the time for appeal ends, the USPTO issues a certificate canceling unpatentable claims, confirming patentable ones and adding any approved substitute claims.
Do you represent patent owners as well as challengers?
Yes. We handle PTAB proceedings and reexaminations for both sides, and the first step is the same, a review of the patent and the record and a fee quoted before any work begins.
[15]Learning Center
Go deeper on IPR and the PTAB.
IPR Can Be Expensive, But Can Be Worth It
One of the most daunting aspects of an Inter Partes Review (IPR) proceeding at the Patent Trial and Appeal Board (PTAB) is the high cost. But the cost of an IPR often…
What Happens After An IPR Decision?
With all the discussion about the potential usefulness of Inter Partes Review (IPR) petitions as a way to seek the invalidation of a patent, petitioners often get excited…
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