An abandoned patent is one that ended before its time. Not the twenty years running out, but a maintenance fee going unpaid and the patent lapsing at the end of a six-month grace period.
It happens to the majority. Of US utility patents granted in 2014, 58.6% were abandoned before reaching full term. That is not an error rate. Most of those decisions were deliberate, and most were probably correct.
Abandonment versus expiry
The two words are used loosely and mean different things to the owner.
| Abandoned | Expired | |
|---|---|---|
| Cause | Unpaid maintenance fee | Statutory term ran out |
| When | 4, 8 or 12 years after grant | 20 years from earliest filing |
| Avoidable | Yes | No |
| Reversible | Sometimes, by petition | Never |
| Effect on third parties | Identical | Identical |
| How common | 58.6% of utility patents | 41.4% |
To anyone else the difference is academic — both mean the invention is free to practise. To the owner it matters, because one was a decision and the other was arithmetic.
The term is also used for applications, which is a separate situation. An application goes abandoned when a deadline during prosecution is missed, most often a response to an office action. That has its own revival route under 37 CFR 1.137 and different consequences — an abandoned application that was already published still counts as prior art, while one abandoned before publication generally does not.
How abandonment happens
No notice is required. The USPTO sends a reminder to the correspondence address of record, but the patent lapses whether or not anybody read it. There is no warning letter, no confirmation, and no final demand.
The sequence at each fee:
| Stage | What happens | Reversible |
|---|---|---|
| Window opens | 6 months before the anniversary | — |
| Window closes | At 3.5, 7.5 or 11.5 years after grant | Yes, grace period follows |
| Grace period | 6 further months, with surcharge | Yes, pay the surcharge |
| Grace period ends | Patent expires. Public domain. | Only by petition |
The whole process takes twelve months from the window opening, and an owner who is not tracking it will usually not notice until well afterwards.
Why patents get abandoned accidentally
Address drift is the largest cause. The correspondence address is set at filing, often to a law firm whose engagement ended at grant. Years later the reminder is sent somewhere nobody reads. Updating it after prosecution costs nothing and is almost never done.
Annuity service lapses. A service is engaged, then dropped during a cost review, and nobody picks up the deadlines it was tracking.
Corporate change. A company is acquired, dissolves, or reorganises, and the patent portfolio falls between the old owner and the new one. Patents held by dissolved entities lapse in large numbers for exactly this reason.
Death of an inventor. The patent passes to the estate, and the estate does not know it exists or does not know what to do with it.
Docketing handover. Counsel changes, files transfer, and one patent falls out of the schedule. Firms that dock hundreds of deadlines lose one occasionally, and the consequence is permanent.
The scale of it
Computed from every maintenance fee event the USPTO has recorded — 27,273,654 rows across 8,262,336 US utility patents granted since 1981.
| Stage | Patents remaining | Abandoned at this stage | Fee |
|---|---|---|---|
| At grant | 100% | — | — |
| After first fee | 85.8% | 14.2% | $2,150 |
| After second fee | 64.6% | 21.2 points | $4,040 |
| After third fee | 41.4% | 23.2 points | $8,280 |
Grant cohort 2014, the most recent to have passed all three windows.
The largest single loss is at the third fee, where 23.2 percentage points of the original cohort drop out. That is the $8,280 payment, and it is where owners who have already invested twice decide a fourth commitment is not worth it for a four-year tail.
Abandonment is rising. Patents granted in 2000 reached full term 51.1% of the time; the 2014 cohort managed 41.4%. The 11.5-year fee went from $3,100 to $8,280 across the same period. Full figures by grant year are on the Ipiry Patent Survival Curve.
But abandonment is front-loaded in a specific population. Of owners who paid the first fee, 74.3% paid the second. Of those, 63.0% paid the third. The people who abandon early are largely those who never had a commercial use for the patent in the first place.
Checking patent status: abandoned or alive
USPTO Patent Center is the authoritative source. Look up the patent and compare recorded maintenance fee payments against the grant date.
Work out the deadlines first. Add 3.5, 7.5 and 11.5 years to the grant date, then six months to each for the grace period. Only stages that have already passed are relevant.
What indicates abandonment: a window and its grace period both closed with no payment recorded against them.
What does not: a missing payment where the grace period is still running. A patent inside its grace period is fully in force, and treating it as abandoned is a serious error — particularly in a freedom to operate context.
Third-party databases lag. Commercial patent tools update maintenance status on their own schedules, and a patent shown as active may have lapsed weeks earlier, or one shown as lapsed may have been revived. For anything that matters, check the USPTO record directly.
Reviving an abandoned patent
The route is 37 CFR 1.378. You petition the USPTO to accept a delayed maintenance fee payment on the basis that the entire delay — from the due date to the petition — was unintentional.
What is required: the outstanding maintenance fee, the petition fee, and a statement that the delay was unintentional. Where the delay has been long, the Office may require further explanation of the circumstances.
Unintentional is not the same as unavoidable. The standard is relatively forgiving. Forgetting counts. A docketing failure counts. An address that went stale counts.
What does not count is a deliberate decision not to pay, later regretted. A patent abandoned on purpose in 2024 because it seemed worthless, and sought to be revived in 2026 because a competitor emerged, is not an unintentional delay — and a statement to the contrary is a statement made to the Office that will not survive scrutiny.
There is no fixed deadline, but the practical position deteriorates with time. A longer lapse makes the petition harder and the intervening rights problem worse.
Intervening rights: why revival is worth less than it looks
This is the part that makes revival less valuable than the fee suggests.
Anyone who began practising the invention in good faith during the lapse may be allowed to continue. They looked at the record, saw an expired patent, and acted on it. The law does not penalise that, and it should not.
The practical consequence is specific and unwelcome. The companies most likely to have started during the lapse are the ones who were watching the patent — checking its status, tracking its family, waiting for it to become free. Which is to say: the most likely infringers, and the most likely buyers.
A revived patent can be enforceable against everybody except the people who mattered.
| Lapse duration | Revival prospects | Intervening rights exposure |
|---|---|---|
| Weeks | Strong | Minimal — nobody had time to act |
| Months | Good | Some, depending on who was watching |
| A year or more | Weaker, more explanation required | Substantial |
Revival is therefore worth most when the lapse was short. A patent revived three months after lapse is close to whole. One revived after two years may be a materially different asset from the one that lapsed.
What an abandoned patent is worth
Almost nothing. There is no exclusive right to sell, no licence to grant, and nothing to assert. The specification remains public and remains prior art, but that is a contribution to the field rather than an asset on a balance sheet.
This is the asymmetry that matters most in the whole maintenance fee decision:
| Timing | Cash | Fee obligation | Outcome |
|---|---|---|---|
| Sold before the window closes | Sale proceeds | Transfers to buyer | Someone else's asset |
| Abandoned at the window | $0 | Ends | Public domain, permanently |
Both outcomes end your fee obligation. Only one pays you for it.
An owner who has decided not to pay the next fee has concluded the patent is worth less than the fee. That is often correct. It does not follow that the patent is worth nothing to anybody — a patent an operating company would pay $40,000 for is still abandoned for want of $8,280 if nobody ever asks them.
The mistake is not abandoning. It is abandoning without checking.
Using technology from an abandoned patent
Generally you can. Three checks before relying on it.
Check the family. Continuations, divisionals and continuations-in-part have their own grant dates and their own fee schedules. A parent lapsing tells you nothing about a child still in force covering adjacent claims. Families are often structured so later members outlive earlier ones.
Check for other patents entirely. Freedom to operate is not established by one patent being dead. Products typically read on claims from several owners, and a proper freedom to operate analysis examines the whole space.
Check whether it might be revived. A patent that lapsed six months ago is still within a realistic revival window. Building a product on it and being met with a revived patent is survivable — intervening rights exist for exactly this situation — but it is a fight you would rather not have.
If you are approaching a fee you do not want to pay
- Confirm the exact deadline, including the grace period end.
- Get a valuation while the patent is alive. It costs nothing to find out what you are about to give up.
- Establish whether anyone practises the claims — that is who would buy it.
- Offer it for sale before the window closes. After that there is nothing to offer.
- Check the rest of the family before letting one member go, because the value may sit in a continuation rather than the patent in front of you.
- Update the correspondence address on anything you do intend to keep.
- If you do let it lapse, do so deliberately — having established it was worth less than the fee, rather than assuming so.