Patent litigation is expensive, slow, and decided earlier than most people expect.
Claim construction is the pivot. How the court reads the claim terms usually determines whether the product infringes and whether the patent survives, and that happens long before trial.
Which is why most cases settle after it. Both sides can suddenly price their positions, and the uncertainty that sustained the dispute is gone.
The practical consequence: getting to claim construction efficiently matters more than preparing for a trial that probably will not happen.
The stages
| Stage | Typical timing | What happens |
|---|---|---|
| Complaint and answer | Months 0–3 | Claims asserted, defences pleaded |
| Initial disclosures | Months 3–5 | Contentions exchanged |
| Infringement contentions | Months 4–6 | Element-by-element mapping |
| Invalidity contentions | Months 6–8 | Prior art asserted |
| Fact discovery | Months 6–18 | Documents, depositions |
| Claim construction briefing | Months 12–18 | Disputed terms briefed |
| Markman hearing and ruling | Months 15–20 | The pivot |
| Expert reports | Months 18–24 | Infringement, validity, damages |
| Summary judgment | Months 24–30 | Issues resolved without trial |
| Trial | Months 30–48 | If it gets there |
| Appeal | +12–24 months | Federal Circuit |
Discovery is where the money goes. Document production, depositions and expert work consume the majority of the budget, and none of it happens in a courtroom.
The gap between filing and claim construction is where cases live or die. Everything before it is preparation for that ruling.
Claim construction, and why it decides things
The court decides what the claim words mean, as a matter of law, at a Markman hearing.
| If a term is construed | Consequence |
|---|---|
| Broadly | Infringement more likely; invalidity also more likely |
| Narrowly | Non-infringement more likely; validity easier to defend |
The construction cuts both ways, which is why parties do not simply argue for the broadest or narrowest possible reading. A patent holder pushing for a construction broad enough to capture the product may capture the prior art too.
Prosecution history constrains it. Everything the applicant argued and amended to get the patent is public, and it limits how broadly the claims can be read. Narrowing to overcome prior art generally surrenders that scope permanently.
Which means the drafting and prosecution done years earlier decides the case. See patent prosecution.
What has to be proved
| Element | Who proves it | Standard |
|---|---|---|
| Every claim element present | Patent holder | Preponderance |
| Literal infringement, or equivalents | Patent holder | Preponderance |
| Invalidity | Accused party | Clear and convincing |
| Willfulness | Patent holder | Preponderance |
| Damages amount | Patent holder | Preponderance |
Every element must be present. Missing one element means no literal infringement, however similar the product is overall. This is the all-elements rule and it is the accused party's first line of defence.
The doctrine of equivalents can bridge a missing element where the difference is insubstantial, but prosecution history estoppel limits it. See doctrine of equivalents.
Invalidity carries a higher standard in court than at the PTAB. Clear and convincing evidence in district court against a preponderance standard before the Board — which is a large part of why IPR became so significant.
Pleadings and contentions
The early paper sets the boundaries of everything that follows.
| Document | Contains | Why it constrains you |
|---|---|---|
| Complaint | Patents asserted, accused products | Adding later is difficult |
| Answer | Defences, counterclaims | Omitted defences can be waived |
| Infringement contentions | Claim-by-claim, element-by-element mapping | Amending later needs leave |
| Invalidity contentions | Every prior art reference relied on | Late references are frequently excluded |
Contentions are where cases are actually framed. They must map every asserted claim element to a specific feature of the accused product, and the mapping is hard to change afterwards.
Prior art not disclosed in invalidity contentions is often lost. Local rules generally require good cause to add references later, which makes early searching essential rather than optional.
Which pushes real work forward. A defendant has months, not years, to find its best prior art. See prior art.
The PTAB alternative
| District court | Inter partes review | |
|---|---|---|
| Decides | Infringement and validity | Validity only |
| Standard for invalidity | Clear and convincing | Preponderance |
| Grounds | Any | §102 and §103 on documents only |
| Timeline | 2–4 years | ~18 months from petition |
| Cost | Seven figures | Substantially less |
| Deadline to file | — | 1 year from service of complaint |
| Estoppel | — | Yes — grounds raised or reasonably could have been |
The one-year bar is absolute. An accused infringer served with a complaint has twelve months to petition, and missing it forfeits the route entirely.
Institution is discretionary and volatile. Rates ran roughly 65% in October 2024 and fell to around 37% by February 2026 — always quote that figure with its date. See inter partes review.
A stay changes the economics completely. District courts frequently stay litigation pending IPR, which pauses the spend and shifts leverage.
Discovery, and why it dominates the budget
| Item | Burden falls on |
|---|---|
| Technical documents and source code | Accused party |
| Sales and financial records | Accused party |
| Engineer depositions | Accused party |
| Conception and reduction to practice records | Patent holder |
| Licensing history | Patent holder |
| Prosecution files | Patent holder |
Source code production is the most expensive single item in software cases, typically involving a secured review environment, restricted access and printed excerpts under protective order.
Protective orders govern everything sensitive. Confidential material is designated by tier, with the most sensitive limited to outside counsel and experts only.
Preserve documents the moment a dispute is foreseeable. Spoliation findings damage a case independently of its merits, and the duty attaches before suit is filed.
Remedies
| Remedy | Availability |
|---|---|
| Reasonable royalty | Statutory floor under §284 |
| Lost profits | Where the holder would have made the sales |
| Enhanced damages | Up to treble, for willful infringement, discretionary |
| Injunction | Four-factor equitable test since eBay |
| Attorney fees | Exceptional cases only, §285 |
| Pre-suit damages | Limited by marking, or by actual notice |
Marking limits damages. A patent holder who practises the invention and does not mark generally cannot recover for the period before actual notice was given. See patent marking.
Injunctions no longer follow automatically. Since eBay v. MercExchange, a patent holder must satisfy the traditional equitable factors, and holders who do not practise the invention obtain them far less readily.
Worked example: where the money goes
A single-patent case against one accused product.
| Stage | Cumulative cost | Cumulative time |
|---|---|---|
| Pre-suit investigation and opinion | $40,000 | — |
| Complaint through answer | $90,000 | Month 3 |
| Contentions exchanged | $180,000 | Month 8 |
| Fact discovery | $550,000 | Month 18 |
| Claim construction briefing and hearing | $750,000 | Month 19 |
| Markman ruling | — | Month 20 |
| Expert reports | $1,100,000 | Month 24 |
| Summary judgment | $1,350,000 | Month 28 |
| Trial | $2,000,000+ | Month 36 |
Where cases actually end
| Resolution point | Share of the total cost incurred |
|---|---|
| Before suit, by licence | ~2% |
| Early settlement | ~10% |
| After claim construction | ~40% |
| After summary judgment | ~65% |
| Through trial | 100% |
Settling after claim construction costs roughly forty per cent of a full trial, and by then the outcome is largely known. That combination is why so many cases end there.
Settling before suit costs almost nothing by comparison, which is the strongest argument for exhausting negotiation first.
Expert witnesses
Three experts appear in most patent cases, and they are a major cost line.
| Expert | Addresses |
|---|---|
| Technical | Infringement and validity, from a skilled person's perspective |
| Damages | Reasonable royalty, lost profits, apportionment |
| Industry or survey | Commercial success, consumer demand, where relevant |
The technical expert defines the person of ordinary skill in the art, which sets the standard for obviousness and for how claim terms are understood.
Damages experts drive the number. Reasonable royalty analysis under the Georgia-Pacific factors, and apportionment where the patented feature is one part of a larger product, are both expert-led. See patent royalty rates.
Expert reports frequently trigger settlement, because they are the first time each side sees the other's quantified case.
What to exhaust first
| Route | Cost | When it fits |
|---|---|---|
| Design around | Engineering time | The claim covers a changeable detail |
| Licence negotiation | Modest | Both sides prefer certainty |
| Mediation | Low | Positions are close |
| Arbitration | Moderate | Contractual relationship exists |
| IPR | Moderate | You have strong documentary prior art |
| Declaratory judgment | High | You need to clear the position proactively |
| Full litigation | Highest | Everything else failed |
Design-around is the cheapest resolution and the most overlooked. If the claim covers a specific detail, changing it ends the dispute without paying anyone.
Check remaining term before committing to anything. A patent with three years left may expire before a case concludes, which changes the calculation entirely. See how long will a patent last.
Who bears what
| Cost | Falls on |
|---|---|
| Own attorney fees | Each side, absent fee shifting |
| Document production | The party holding documents |
| Expert fees | Each side, for its own experts |
| Court costs | Usually the losing party, modest |
| Fee shifting | Exceptional cases only, §285 |
The American rule applies. Each side pays its own way regardless of outcome, which is what makes cost asymmetry decisive rather than merely uncomfortable.
Venue and forum
Venue is constrained. Under TC Heartland, a domestic corporation may be sued where it is incorporated or where it has a regular and established place of business — which ended the practice of filing anywhere.
| Consideration | Effect |
|---|---|
| District local patent rules | Timing of contentions and claim construction |
| Time to trial | Varies substantially by district |
| Stay practice on IPR | Some districts stay readily, some rarely |
| Judge experience | Familiarity with patent issues |
Local patent rules matter more than most people expect. They set when contentions are due and how quickly claim construction happens, which drives the whole cost curve.
Willfulness and opinions
Enhanced damages turn on conduct after notice, not on the strength of the patent.
| Factor | Effect on willfulness |
|---|---|
| Knowledge of the patent | Necessary |
| Continuing without a reasoned basis | Supports enhancement |
| A written opinion of counsel | Principal defence |
| Copying | Supports enhancement |
| A genuine design-around attempt | Weighs against |
| Reasonable invalidity belief | Weighs against |
Enhanced damages are discretionary, up to three times the award under §284, and awarded for egregious conduct rather than as a routine uplift.
The opinion must predate the continued conduct to do its job. One obtained after suit is filed addresses litigation strategy, not the state of mind that mattered.
Which is the practical reason to act on monitoring findings rather than filing them. See freedom to operate.
The asymmetry problem
Cost falls unevenly, and that shapes outcomes independently of merits.
| Patent holder | Accused party | |
|---|---|---|
| Can stop the dispute unilaterally | No | Yes — design around |
| Faces business disruption | No | Yes |
| Discovery burden | Lower | Much higher |
| Can afford to lose | Depends | Depends |
Discovery burden falls disproportionately on the operating company, which holds the documents, the engineers and the sales records. A non-practising plaintiff has comparatively little to produce.
Which is a substantial part of the settlement dynamic, and the reason nuisance settlements exist. See patent trolls.
Settlement structures
| Structure | Typical use |
|---|---|
| Lump sum licence | Clean exit, no ongoing relationship |
| Running royalty | Where volume is uncertain |
| Cross-licence | Both parties hold relevant patents |
| Covenant not to sue | Narrower than a licence, no transfer of rights |
| Patent purchase | The accused party buys the patent outright |
| Walk-away | Both sides drop, each bears its own costs |
A covenant not to sue is narrower than a licence and is often preferred by a patent holder, because it binds only the parties rather than granting rights that travel with products.
Buying the patent outright resolves everything permanently and is underconsidered — it removes the asset from the market rather than licensing it.
Appeal
The Federal Circuit hears every patent appeal, which produces more consistency than regional circuits would but also concentrates the risk.
| Issue | Standard on appeal |
|---|---|
| Claim construction | Reviewed de novo for intrinsic evidence |
| Underlying factual findings | Clear error |
| Infringement | Substantial evidence, from a jury |
| Obviousness | Legal conclusion, de novo; facts for clear error |
| Damages | Abuse of discretion, largely |
De novo review of claim construction is the significant one. The Federal Circuit reconsiders the pivotal ruling from scratch on the intrinsic record, which means a case decided on construction is genuinely open on appeal.
Appeal adds a year or more and its own cost. Factoring it into settlement analysis is standard, because a district court win is not final.
Patent litigation: the checklist
- Exhaust design-around, licensing and mediation first. Litigation is the most expensive route by a wide margin.
- Read the prosecution history before doing anything. It constrains claim construction and it is public.
- Calculate remaining patent term. A case can outlast the patent.
- Diarise the one-year IPR bar from service of the complaint. It cannot be extended.
- Assess your documentary prior art early. It determines whether IPR is available as a route.
- Get an opinion before continuing a known risk. It is the principal defence against enhanced damages for willfulness.
- Budget to claim construction, not to trial. That is where most cases end.
- Check marking compliance if you are asserting — it limits pre-notice damages.
- Model the cost asymmetry honestly, including who bears the discovery burden.
- Decide your settlement position before the Markman ruling, because everyone's leverage changes the day it issues.