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Patent opposition

Clear the patent in your way, or defend the one that protects you.

Opposition is the fastest and most cost-effective way to remove or narrow a patent that stands in your way, and the moment a patentee must be ready to defend its claims. We prepare notices and statements, build the evidence, answer every reply and argue the case at hearing, for opponents and patentees in every major office.

  • Pre-grant and post-grant oppositions at the EPO, IP India, JPO, KIPO, IP Australia and more
  • Evidence, expert declarations and hearings handled end to end
  • Parallel proceedings coordinated across offices and courts, under one strategy
20+Years in patent practice
150+Jurisdictions coordinated
Both sidesOpponents and patentees

Discuss your opposition

Share the patent and your deadline. An attorney replies within one business day with an assessment and fees.

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Confidential. Reviewed only by our patent attorneys.
What it is

The patent office's second look, on your evidence.

An opposition asks the patent office to refuse, revoke or narrow a patent, usually because earlier prior art shows the invention is not new or not inventive, or because the patent does not disclose the invention sufficiently. Depending on the office, it can be filed before grant, after grant, or both.

For an opponent, it is a way to clear a blocking patent in an administrative forum, at a fraction of the cost and time of court litigation. For a patentee, it is the moment the claims are tested in earnest, and how they are defended will shape their value in every licence, sale and lawsuit that follows.

At a glance

Filed by
Competitors, licensees or any third party
Defended by
The patentee, often with amended claims
Common grounds
Novelty, inventive step, sufficiency, added matter
Timing
Fixed windows, from pre-grant to 12 months after grant
Outcome
Patent maintained, amended or revoked
Compared with court
Faster, lower cost, technical tribunal
Our opposition services

Every stage of the proceeding, handled by one team.

From the first assessment to the final hearing, our patent attorneys and technical specialists work as one team, for opponents and patentees alike.

01

Notice filing and opposition drafting

A notice that frames the whole case. We select the strongest grounds, fix the claim construction early and draft a statement of case an examiner or opposition division can follow from the first page.

  • Grounds chosen per office: novelty, inventive step, sufficiency, added matter, eligibility
  • Claim-by-claim attack charts with ranked prior art
  • Problem-solution and obviousness arguments built per claim
  • Pre-grant representations and post-grant notices
  • Straw man and nominee filing where permitted
  • Strict compliance with form, fee, language and filing rules
02

Evidence preparation

Oppositions are won on evidence. We find it, prove its date and present it so the tribunal can rely on it without question.

  • Worldwide patent and non-patent prior art searches
  • Proof of public availability, prior use and publication dates
  • Expert declarations and affidavits from technical specialists
  • Comparative test data and experimental evidence, where needed
  • Certified translations of foreign-language art
  • Archived web, product and trade show evidence
03

Replies, rejoinders and sur-rejoinders

Every round of pleadings is a chance to narrow the issues in your favour. We answer each point, close gaps and keep the record consistent.

  • Reply statements and reply evidence for opponents
  • Counter-statements and amended claim requests for patentees
  • Rejoinders and sur-rejoinders that rebut new arguments
  • Auxiliary requests prepared as fallback positions
  • Responses to preliminary opinions and summons
  • Late-filed evidence and admissibility arguments
04

Hearing representation

Clear, prepared advocacy before opposition divisions, controllers and boards, with written submissions that leave nothing to chance.

  • Hearing strategy and written submissions
  • Oral argument before the opposition board or division
  • Witness and expert preparation, including hearing of witnesses
  • Real-time handling of new requests at the hearing
  • Post-hearing written submissions where allowed
  • Decision review and appeal assessment
05

Foreign opposition coordination

One strategy across every office where the patent family is granted, so positions taken in one forum do not undermine another.

  • Parallel oppositions at the EPO, JPO, KIPO, IP Australia and IP India
  • Invalidation, PGR and IPR coordinated with local counsel
  • Consistent claim construction across the family
  • Shared evidence and expert pool across proceedings
  • Monitoring of decisions in one office for use in another
  • One point of contact and one consolidated report
06

Opposition vs revocation strategy

Opposition is not always the right tool. We weigh cost, timing, standard of proof and estoppel to choose the route that best serves your commercial goal.

  • Opposition, revocation, invalidation or re-examination compared
  • Timing against launch plans and litigation
  • Risk of estoppel and impact on later court action
  • Interplay with infringement proceedings and injunctions
  • Settlement and licensing leverage assessed
  • Budget and duration forecast for each route
Grounds of opposition

Every ground that can bring a patent down.

The available grounds differ by office. We identify every ground that applies to the patent in question and lead with the strongest.

Lack of novelty

A single earlier document, use or disclosure that shows every feature of the claim.

Lack of inventive step

The claim would have been obvious to a skilled person in light of the prior art, alone or in combination.

Insufficient disclosure

The patent does not teach a skilled person how to carry out the invention across the full scope claimed.

Added matter

The granted claims or description contain subject matter that was not in the application as filed.

Excluded subject matter

Claims directed to subject matter that the law excludes, such as abstract ideas, methods of treatment or mere discoveries.

Prior public use and knowledge

The invention was used, sold or known publicly before the priority date, proven by documents and witnesses.

Entitlement and wrongful obtaining

The patentee was not entitled to the invention, or obtained it from the opponent or another person.

Local statutory grounds

Office-specific grounds, such as non-disclosure of foreign filings or efficacy requirements for known substances in India.

Inadmissible amendments

Amendments during opposition that add matter, extend protection or lack clarity, challenged as they are filed.

Which side are you on?

Challenging a patent or defending one.

We act for opponents and patentees, so we know how each side builds its case, and where it is weakest.

For opponents

Challenging a patent

Remove or narrow the patent blocking your way.

  • Watch competitor grants so no window is missed
  • Assess prospects and cost before you commit
  • Choose the office, the grounds and the timing
  • File through a nominee to keep your identity confidential, where allowed
  • Search for the decisive prior art and prove its date
  • Build attack charts and obviousness arguments
  • Engage experts and run comparative tests
  • Answer the patentee's amendments and auxiliary requests
  • Argue the case at hearing and on appeal
  • Use the result in licensing, litigation or launch decisions
For patentees

Defending your patent

Keep claims that still cover what matters commercially.

  • Assess the notice and the real strength of each ground
  • Map the claims to your products and licences
  • Prepare amendments that keep commercial scope
  • Build a clear hierarchy of auxiliary requests
  • Answer prior art with technical effect and evidence
  • Engage experts and run experiments where useful
  • Challenge late-filed or weak evidence
  • Keep positions consistent with litigation and other offices
  • Argue the case at hearing and on appeal
  • Plan divisionals and continuations as a safety net
Where we act

Every major office, one coordinated strategy.

Each office has its own procedure, deadline and standard of proof. We act directly or with trusted local counsel, and keep every proceeding in the family aligned.

EuropeEPO
Proceeding
Post-grant opposition
When to file
9 months from the mention of grant
IndiaIP India
Proceeding
Pre-grant and post-grant opposition
When to file
Pre-grant until grant; post-grant within 12 months of grant publication
JapanJPO
Proceeding
Post-grant opposition
When to file
6 months from publication of the patent gazette
South KoreaKIPO
Proceeding
Patent cancellation request
When to file
6 months from publication of registration
AustraliaIP Australia
Proceeding
Pre-grant opposition
When to file
3 months from advertisement of acceptance
New ZealandIPONZ
Proceeding
Pre-grant opposition
When to file
3 months from advertisement of acceptance
United StatesUSPTO / PTAB
Proceeding
Post-grant review and inter partes review
When to file
PGR within 9 months of grant; IPR after that
ChinaCNIPA
Proceeding
Invalidation request
When to file
Any time after grant
United KingdomUKIPO
Proceeding
Revocation and examiner opinions
When to file
Any time after grant
BrazilINPI
Proceeding
Administrative nullity
When to file
Within 6 months of grant
CanadaCIPO
Proceeding
Re-examination
When to file
Any time after grant
SingaporeIPOS
Proceeding
Re-examination and revocation
When to file
Any time after grant

Opposition windows are strict and usually cannot be extended. Periods are summarised here for guidance; we confirm the exact deadline for every patent.

Evidence that wins

The proof behind every argument.

Arguments only persuade when the evidence behind them is dated, complete and credible. We build the evidence base as carefully as the arguments.

Patent and literature prior art

Worldwide patents, journal papers, theses, standards and conference proceedings, with publication dates verified.

Prior public use

Products sold, shown or used before the priority date, proven with invoices, catalogues, photographs and witnesses.

Expert declarations

Independent experts explaining the common general knowledge and why the claimed solution was obvious, or not.

Experimental evidence

Comparative tests and reproductions that prove or disprove technical effects relied on by the patentee.

Archived web and product evidence

Archived pages, manuals, app versions and videos, captured with dates and preserved for verification.

Translations and certified copies

Certified translations and official copies prepared to meet each office's formal requirements.

Choosing the route

Opposition or revocation? The answer depends on your goal.

The best forum is the one that delivers your commercial outcome at the right time and cost. We set out the options before you commit.

Administrative route

When opposition is the better tool

A technical tribunal, a lower cost, one central attack.

  • The opposition window is still open
  • You want to attack a European patent centrally, in every country at once
  • Technical prior art is your strongest argument
  • You want a lower-cost route than court action
  • You want a result before launch or litigation
  • You prefer to stay out of court for now
  • You want to keep your identity confidential through a nominee
  • You need the patent narrowed, not only revoked
Court and invalidation route

When revocation or invalidation fits better

Wider evidence, binding effect, no fixed window.

  • The opposition window has closed
  • You are already in, or expect, an infringement suit
  • You need cross-examination or disclosure of documents
  • You want the decision tied to the infringement case
  • The patent is national only, with no opposition procedure
  • Settlement leverage matters more than speed
  • Prior use evidence depends on witness testimony
  • You need a declaration of non-infringement as well
How an opposition runs

From the first assessment to the final decision.

A disciplined process keeps every deadline met and every argument consistent from notice to hearing, and into appeal if needed.

  1. 01

    Watch and assess

    Grant dates tracked; claims, file history and prospects reviewed.

  2. 02

    Grounds and evidence

    Prior art searched, dates proven and experts engaged.

  3. 03

    Notice and statement

    Filed on time, with claim charts and evidence attached.

  4. 04

    Exchange of pleadings

    Replies, rejoinders and sur-rejoinders, with auxiliary requests.

  5. 05

    Hearing

    Written submissions and oral argument before the tribunal.

  6. 06

    Decision and appeal

    Decision reviewed, with appeal or settlement options set out.

Deadlines are absolute

Most opposition windows cannot be extended, and once they close the only routes left are slower and costlier. We watch grant dates for the patents that matter to you, so you never miss the window.

Check your deadline
Ways to work with us

From a single notice to a global campaign.

Choose the engagement that fits your situation. Each can be scaled up as the matter develops.

Option 01 of 06

Opposition watch

Competitor patents tracked from publication to grant, so you never miss an opposition window and can plan budgets ahead.

  • Grant alerts for chosen competitors and technologies
  • Early prospects review on each relevant grant
  • Docketing of every opposition deadline
  • Third-party observations before grant where useful
  • Budget planning for likely oppositions
  • Quarterly watch reports
Discuss this option
Industries we serve

Technical depth in the fields shaping what comes next.

Our attorneys and technical specialists work in the technologies where filing activity is growing fastest, so technical grounds are argued by people who understand the science.

Artificial intelligence & ML

Models, training methods and AI applications

Semiconductors

Chip design, fabrication and packaging

Telecom, 5G & IoT

Wireless standards, networks and connected devices

Electric vehicles & mobility

Batteries, charging and drive systems

Clean energy & climate tech

Solar, storage, hydrogen and carbon capture

Robotics & automation

Industrial robots, control and machine vision

Medical devices & digital health

Devices, diagnostics and health software

Biotechnology & genomics

Biologics, gene editing and sequencing

Pharmaceuticals

Formulations, processes and new uses

Fintech & digital payments

Payments, security and financial platforms

Consumer electronics & wearables

Devices, sensors and user interfaces

Advanced materials & chemistry

Materials, polymers and chemical processes
Why AnalystIP

Contentious experience with technical depth.

Global companies and law firms rely on us when a single patent can decide a product line, a licensing programme or a deal.

Contentious patent attorneys

Practitioners who draft, argue and defend oppositions as a core practice, not an occasional one.

Technical specialists in every field

Engineers and scientists who understand the art as well as the opposing experts do.

Search that finds the decisive art

In-house searchers who look beyond patents to papers, standards, products and archives.

Global coordination

Parallel proceedings managed under one strategy, with consistent positions across offices and courts.

Both sides of the table

Experience for opponents and patentees, so we anticipate the other side's moves.

Deadline discipline

Every window docketed on grant, with internal deadlines well ahead of the official ones.

Commercially focused advice

Every recommendation tied to your launch, licensing or litigation goals.

Clear reporting

Plain-language updates and decision points for in-house teams and boards.

Confidential and conflict-checked

Strict confidentiality and conflict checks on every matter, with discreet filing options where available.

FAQs

Questions about patent oppositions.

Answers to what IP teams and counsel ask us most.

An opposition window closing?

Send us the patent number. We will confirm the deadline and our assessment within one business day.

Discuss your opposition
01What is a patent opposition?

A proceeding before the patent office in which a third party asks for a patent or application to be refused, revoked or limited. It is decided by the office, not a court, and is usually faster and less costly than litigation.

02What is the difference between pre-grant and post-grant opposition?

A pre-grant opposition is filed after publication but before the patent is granted, as in India, Australia and New Zealand. A post-grant opposition is filed within a fixed period after grant, as at the EPO, the JPO and in India.

03What grounds can be raised?

Typically lack of novelty, lack of inventive step, insufficient disclosure, added matter and non-patentable subject matter. The exact grounds vary by office, and some offices add local grounds, such as prior public use or non-disclosure of foreign filings in India.

04Can I oppose without revealing my identity?

Some offices, including the EPO, allow an opposition to be filed by a straw man or nominee, which keeps the real opponent confidential. We advise on whether this is available and sensible in your case.

05How long does an opposition take?

It varies widely by office and by how many rounds of pleadings are exchanged. We give you an expected timeline and budget at the outset, and update it as the case develops.

06Can the patentee amend the claims during opposition?

Yes, within limits. Patentees usually file a main request and auxiliary requests with narrower claims. Amendments must not add matter or extend protection, and opponents can challenge them on those grounds.

07What happens if the opposition window has closed?

Other routes remain, such as revocation or invalidation actions, re-examination, or IPR in the US. They differ in cost, timing and standard of proof, and we compare them for you.

08Do you defend patents in opposition as well?

Yes. We act for patentees, preparing counter-statements, amended claims and auxiliary requests, expert evidence and hearing submissions to keep the claims commercially meaningful.

09Can you coordinate oppositions in several countries?

Yes. We run parallel proceedings across the patent family with local counsel where needed, keeping arguments and claim construction consistent everywhere.

10Can we appeal an opposition decision?

Yes, in most offices. At the EPO, appeals go to the Boards of Appeal. We assess the decision, the chances on appeal and the cost before recommending whether to proceed.

Related services
Validity & invalidityPrior art that decides cases
Claim chartsElement-by-element mapping
Freedom to operateFind blocking patents early
Office action responseProsecution to grant
Act before the window closes

One patent can block a product line. Let's deal with it.

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