Summary. A patent is only as enforceable as its chain of title, and the most expensive discovery in patent litigation is that the plaintiff does not own what it is asserting. This article explains who owns an invention at conception, why inventorship and ownership are different questions with different consequences, and how Stanford v. Roche confirmed that even federally funded inventions vest first in the inventor. It works through assignment drafting, including the decisive difference between a present assignment and a mere promise to assign, the treatment of future inventions, and state statutes limiting what an employer may claim. It then addresses standing: who may sue, what a patentee must hold to sue alone, when an exclusive licensee may sue in its own name, and how Lone Star Silicon reframed much of this as statutory rather than jurisdictional. Sections on correction of inventorship, recordation and bona fide purchasers, security interests, Bayh-Dole, and shop rights follow, with a diligence checklist, a worked example, an FAQ, and related reading.

Three years into a patent case, on the eve of trial, the defendant's counsel notices something in a document produced months earlier. The named inventor signed his employment agreement on his second day of work. The invention disclosure is dated four days before that.

If the agreement says the employee "agrees to assign" future inventions, and the invention was conceived before the agreement was signed, the plaintiff may not own the patent. Not a technicality about paperwork. It may not own it.

Chain of title is the least glamorous subject in patent law and one of the most decisive. It is also almost entirely preventable, and the preventive measures cost a few sentences in a form document.

The short answer

  • An invention is owned initially by its inventors. Every one of them, as tenants in common in the whole, regardless of who paid or who owns the lab.
  • 35 U.S.C. § 261 makes patents and applications assignable, but only "by an instrument in writing."
  • Words matter enormously. "Hereby assigns" effects an immediate transfer of a future invention when it comes into being. "Agrees to assign" creates only a contractual obligation, leaving legal title with the inventor until a further document is signed.
  • Joint owners each own the whole. Absent agreement, each may make, use, sell, and license the invention without accounting to the others, § 262 — a harsher rule than copyright's.
  • All co-owners must join a suit. One co-owner cannot sue alone, and one co-owner can grant a license that destroys the case.
  • An exclusive licensee may sue in its own name only if it holds "all substantial rights"; otherwise it must join the patentee.
  • Recordation at the USPTO within three months protects against subsequent bona fide purchasers. § 261.

Part I: Inventorship

Inventorship is not authorship, and it is not a courtesy

The inventors are the people who conceived the invention as claimed. Conception is the formation in the mind of a definite and permanent idea of the complete and operative invention, such that only ordinary skill is needed to reduce it to practice.

Who is not an inventor:

  • The person who funded the work.
  • The supervisor who assigned the project and set the goal.
  • The technician who built and tested what someone else conceived, exercising only ordinary skill.
  • The person who suggested the problem without contributing to the solution.
  • The lawyer who drafted the claims.

Who is an inventor:

  • Anyone who contributed to the conception of at least one claim. Under § 116(a), joint inventors need not work in the same place, at the same time, or make the same type or amount of contribution, and need not have contributed to every claim.

Why it matters

Inventorship is claim-specific and it drives ownership. Each inventor of any claim owns an undivided interest in the entire patent, not just that claim. So adding an inventor for one dependent claim gives that person co-ownership of everything.

Getting it wrong is dangerous in both directions. Deliberately omitting an inventor, or adding one who did not invent, can render the patent unenforceable for inequitable conduct if done with deceptive intent, and it can hand an accused infringer a license from the omitted inventor after correction.

Correction under § 256

Errors are correctable. Section 256 provides that where a person is named who is not an inventor, or an inventor is not named, "and such error arose without any deceptive intention on his part," the Director may issue a certificate correcting the error, and a court may order correction on notice and hearing.

The AIA removed the "without deceptive intent" language from the analogous § 116 provision and softened the framework, and the Federal Circuit has treated § 256 as a savings provision that should be applied to preserve patents where the error was innocent. But correction litigation is expensive and it usually arrives as a counterclaim asserted by a defendant who has found a disgruntled former colleague.

The practical guidance: determine inventorship claim by claim at filing, revisit it after every claim amendment (narrowing or adding claims can change who invented what), and document the analysis. See Preparing an Invention Disclosure.

Part II: Ownership and assignment

The default rule survived Bayh-Dole

Board of Trustees of the Leland Stanford Junior University v. Roche Molecular Systems, Inc., 563 U.S. 776 (2011), is the case that settles the baseline. A Stanford researcher signed a Stanford agreement saying he "agree[d] to assign" his inventions, then visited a company called Cetus and signed an agreement saying he "will assign and do[es] hereby assign" his inventions there. He later worked on federally funded HIV-detection research at Stanford. Stanford sued Roche (Cetus's successor) and argued that the Bayh-Dole Act gave the university title to inventions made with federal funding.

Chief Justice Roberts's opinion is emphatic: "Since 1790, the patent law has operated on the premise that rights in an invention belong to the inventor." Bayh-Dole does not "automatically vest title to federally funded inventions in federal contractors"; it operates on inventions the contractor already owns. And because the Cetus agreement was a present assignment while the Stanford agreement was a promise to assign, Cetus's successor took title first.

Two lessons, both operational:

  1. Federal funding does not give the institution title. Bayh-Dole gives the contractor an option to elect title to a "subject invention" it owns, subject to disclosure deadlines, a government license, march-in rights, and U.S. manufacturing preferences. It does not do the assignment for you.
  2. The verb tense decided a Supreme Court case.

"Hereby assigns" versus "agrees to assign"

FilmTec Corp. v. Allied-Signal Inc., 939 F.2d 1568 (Fed. Cir. 1991), established the rule Stanford applied. An agreement providing that the employee "agrees to grant and does hereby grant" rights in future inventions effects a present assignment of an expectant interest: when the invention comes into being, legal title passes automatically, with no further act required.

By contrast, an agreement that the employee "agrees to assign" is a promise. Legal title remains with the inventor until a confirmatory assignment is executed. In the interval:

  • The employee can assign to someone else, and a bona fide purchaser may take good title.
  • The employer holds an equitable interest, which must be converted to legal title by suit or by a later signature.
  • The employer cannot sue for infringement, because it is not the patentee.

Draft the present-tense form, always:

Employee hereby irrevocably assigns, transfers, and conveys to Company all right, title, and interest in and to all Inventions conceived or reduced to practice, alone or with others, during the period of employment and within the scope of Company's business or resulting from work performed for Company, together with all patents, applications, and rights of priority therein, and all rights to sue for and recover damages for past, present, and future infringement.

Add a further assurances clause and a power of attorney authorizing the company to execute documents if the employee is unavailable or uncooperative, which is invaluable years later when an inventor has left and will not return calls.

Timing: sign before day one

The Stanford trap is a timing trap. An assignment executed after conception still works between the parties, but it leaves a window in which the inventor held title and could have transferred it. Get agreements signed before the employee starts work, and confirm in the offer letter that execution is a condition of employment. For anyone joining mid-project, add a schedule listing pre-existing inventions the employee is excluding, so the boundary is documented rather than argued later.

State-law limits on employee assignment

Several states restrict what an employer may claim. California Labor Code § 2870 is the model, followed in substance by Delaware, Illinois, Kansas, Minnesota, North Carolina, Utah, Washington, and others. Such statutes void a provision requiring assignment of an invention the employee developed entirely on their own time without using the employer's equipment, supplies, facilities, or trade secret information, except inventions that (a) relate at the time of conception or reduction to practice to the employer's business or actual or demonstrably anticipated research or development, or (b) result from work performed for the employer.

California also requires written notice of the statute to the employee, § 2872. An agreement that omits the required notice or that overreaches can be unenforceable as to the overreaching part, and in some states can taint the clause.

Drafting response: include the statutory carve-out and the notice by reference, and keep a state-by-state rider. See Employee Invention Assignment Agreements.

Hired to invent, and shop rights

Two common-law doctrines fill gaps when there is no written agreement, and neither is a substitute for one.

Hired to invent. Where an employee was specifically hired or directed to solve a particular problem, courts may find an implied-in-fact contract to assign the resulting invention. The doctrine is narrow and fact-dependent; general research employment is not enough.

Shop right. Where an employee uses the employer's time, materials, or facilities to make an invention, the employer receives a non-exclusive, non-transferable, royalty-free license to practice it. A shop right is a defense, not ownership. It does not permit the employer to license others, to sue infringers, or to sell the right apart from the business.

An employer relying on either doctrine has already lost the argument it should have won with a signature.

Joint ownership: the harsh rule

Section 262 provides that, in the absence of any agreement to the contrary, each of the joint owners may make, use, offer to sell, sell, or import the patented invention without the consent of and without accounting to the other owners.

Read that twice. Unlike copyright, there is no duty to account. A ten percent co-owner may license your competitor for a dollar and keep the dollar.

And for enforcement: all co-owners must be joined as plaintiffs. A co-owner who refuses to join can defeat the suit entirely, subject to narrow exceptions where a co-owner has contractually waived the right to refuse or where the co-owner has granted an exclusive license obliging it to join.

Consequences to plan around:

  • Joint development agreements must allocate ownership expressly and must address enforcement, licensing consent, and accounting. Silence produces § 262.
  • University collaborations, consortium work, and joint ventures are the recurring sources of accidental co-ownership.
  • Adding a co-inventor from a collaborator organization creates co-ownership with that organization by operation of its own assignment agreements.

Part III: Standing to sue

The statutory framework

Section 281 provides that "[a] patentee shall have remedy by civil action for infringement of his patent." Section 100(d) defines "patentee" to include successors in title.

For decades the Federal Circuit spoke of "constitutional standing," "prudential standing," and "statutory standing" in patent cases, and dismissals for lack of standing were common. Lone Star Silicon Innovations LLC v. Nanya Technology Corp., 925 F.3d 1225 (Fed. Cir. 2019), clarified the framework considerably: whether a plaintiff holds enough rights to sue in its own name under § 281 is a statutory question, not a jurisdictional one, and a plaintiff that lacks all substantial rights may be able to cure the defect by joining the patentee rather than suffering dismissal. Article III standing is a separate and lower bar: a party with exclusionary rights that are being violated has suffered injury in fact.

The practical upshot: chain-of-title defects are still serious, but they are more often curable than they were, provided the necessary party can be joined.

Who may sue alone

  • The patentee (the assignee of all substantial rights) may sue alone.
  • An exclusive licensee holding all substantial rights is treated as the effective patentee and may sue alone. Courts look past labels to the substance of the agreement.
  • An exclusive licensee holding less than all substantial rights has standing but must join the patentee.
  • A bare licensee (non-exclusive) has no right to sue, ever, and cannot be given one by contract language alone.

What "all substantial rights" means

Courts weigh a list of factors, and no single one controls. The two most important are:

  1. The exclusive right to enforce, including who controls litigation and settlement; and
  2. The scope of the right to practice and exclude, including field-of-use, territorial, and time limits.

Other factors: the right to sublicense; the right to assign; the patentee's retained right to sue; obligations to pay the patentee a share of recoveries; the duration of the grant relative to the patent term; the patentee's retained right to practice; reversionary rights; and any retained veto over settlement.

A retained right to sue in the patentee's own discretion is usually fatal to the licensee's ability to sue alone.

Practical instructions

For plaintiffs. Before filing, assemble the complete chain from each named inventor to the current plaintiff, with signed and dated documents at every link. Confirm no gap, no unassigned co-inventor, and no intervening entity that dissolved without transferring. If suing as an exclusive licensee, either take all substantial rights by amendment or plan to join the patentee at the outset.

For defendants. Chain of title is a first-week discovery priority. Request every assignment, employment agreement, joint development agreement, and corporate merger document in the chain. Look for:

  • "agrees to assign" language;
  • assignments executed after conception;
  • a co-inventor whose employer never assigned;
  • entities in the chain that merged, converted, or dissolved without a documented transfer;
  • security interests and foreclosures;
  • prior exclusive licenses that were never disclosed;
  • inventorship errors supporting a § 256 counterclaim.

A chain-of-title defense does not usually end a case outright after Lone Star, but it can force joinder of an unwilling party, expose a prior license that moots the claim, or delay the case at a cost the plaintiff did not budget for.

Part IV: Recordation, security interests, and government rights

Recordation and bona fide purchasers

Section 261 provides that an assignment "shall be void as against any subsequent purchaser or mortgagee for a valuable consideration, without notice, unless it is recorded in the Patent and Trademark Office within three months from its date or prior to the date of such subsequent purchase or mortgage."

So: record within three months, or at least before the next transaction. Recordation is inexpensive, is done electronically through the USPTO's assignment system, and is the only protection against a later good-faith purchaser.

Note what recordation does not do: it does not validate a defective assignment, and it does not create title where none was conveyed. A recorded document that says "agrees to assign" is a recorded promise, not a recorded transfer.

Security interests

Patents can secure debt, and the perfection question has a trap. Perfection of a security interest in a patent as general intangible collateral is accomplished by filing a UCC-1 with the appropriate state, not by recording at the USPTO. The Patent Act's recording provision addresses assignments, and courts have generally held that it does not preempt the UCC for security interests short of an outright transfer.

Prudent lenders therefore do both: file the UCC-1 for perfection and record a conditional assignment or a notice at the USPTO to defeat a later bona fide purchaser who searches only the federal register. Borrowers should confirm that a recorded conditional assignment does not, by its terms, transfer title before default, because a lender that appears on the assignment record as owner creates confusion in later diligence and can complicate standing.

Government rights under Bayh-Dole

Where an invention is made with federal funding, the Bayh-Dole Act, 35 U.S.C. §§ 200-212, and its regulations at 37 C.F.R. Part 401 impose obligations on the contractor that owns the invention:

  • Disclose the subject invention to the funding agency within a defined period.
  • Elect title within a defined period, or the agency may take title.
  • File patent applications within defined periods.
  • Include a government license: a nonexclusive, nonassignable, irrevocable, paid-up license to practice the invention for or on behalf of the United States.
  • Include the government-support clause in the patent's specification.
  • Give preference to U.S. manufacture for exclusive licenses to use or sell in the United States.
  • Accept march-in rights, under which the agency may require licensing in defined circumstances (rarely exercised, periodically debated).

Missing the disclosure or election deadlines can cost title. In diligence, always check whether the specification contains a government-support statement, and if it does, ask for the Bayh-Dole compliance file.

Part V: Ownership in the structures where it usually breaks

Chain-of-title problems cluster in a handful of arrangements. Each has a known fix.

University spin-outs. The founder was a faculty member or a graduate student, the institution's IP policy assigns inventions made with institutional resources, and the company was formed around technology the university may own. The fix is a written license or assignment from the technology transfer office before the company raises money, plus a clear statement of what the founder invented before and after the relevant date. Investors will ask; the diligence question is standard.

Consultants and fractional CTOs. The most common gap in early-stage companies. A consultant is not an employee, so there is no scope-of-employment argument and no hired-to-invent presumption worth relying on. Every consulting agreement needs a present assignment, and the company should not pay a final invoice until it is signed.

Joint development agreements. Two companies co-develop, both contribute inventors, and the agreement says the parties will "jointly own" the results. That sentence, standing alone, invokes § 262: either party may license anyone, without accounting, and neither can sue alone. Allocate expressly: who owns what subject matter, who prosecutes, who pays, who may license and on what terms, who controls enforcement, and how recoveries are shared. If joint ownership is genuinely intended, contract around § 262 explicitly.

Standards and consortium work. Contributions to a standards body may carry licensing commitments that attach to any patent covering the standard, sometimes regardless of who owns it. Track which employees participate in which working groups. See Standard Essential Patents and FRAND Licensing in 5G and IoT.

Acquisitions and dissolved entities. A patent assigned to an entity that later merged, converted, or dissolved leaves a record that no longer matches reality. Transfers by operation of law are effective but invisible on the assignment register. Record the certificate and a confirmatory assignment at each step. Reconstructing a chain through three dissolved LLCs a decade later is a genuinely difficult exercise.

Open innovation and hackathons. Contributions from people with no agreement at all. If the output matters, get assignments at the door as a condition of participation, and understand that a participant employed elsewhere may be unable to assign at all.

Part VI: Foreign counterparts and inventor remuneration

Ownership rules are not universal, and a portfolio filed abroad on American assumptions can produce surprises.

Employer ownership by statute. Many civil law jurisdictions vest service inventions in the employer by operation of law, subject to notification procedures and, importantly, to statutory compensation owed to the inventor. Germany's Act on Employees' Inventions is the best-known example, with a formal claiming procedure and a compensation formula; Japan, China, Korea, France, and others have their own regimes. A U.S. company with inventors abroad may owe inventor compensation it never budgeted for, and the obligation is often not waivable by contract.

Assignment formalities differ. Some jurisdictions require notarization or legalization, some require recordation for effectiveness against third parties rather than merely for priority, and some require the assignment to be in the local language.

Foreign filing licenses. Section 184 requires a license before filing abroad an application on an invention made in the United States, ordinarily granted automatically by the filing receipt after six months or by petition. Other countries impose the mirror-image requirement for inventions made there. Filing abroad first without a required license can invalidate the corresponding U.S. patent, and this catches distributed engineering teams routinely.

Practical response: maintain a matrix of where your inventors actually sit, apply local assignment formalities at hiring, budget for statutory inventor compensation in the relevant jurisdictions, and route every first filing through a foreign-filing-license check. See Global Patent Litigation Strategies.

A worked example

Halden Photonics, Inc. (fictional) is preparing to assert U.S. Patent No. 10,XXX,XXX against a competitor. Diligence surfaces four problems.

Problem 1: the second inventor. The patent names two inventors. The second, Dr. Rios, was a postdoctoral researcher at a university collaborating under a sponsored research agreement. Halden has an assignment from the first inventor only.

Analysis. If Dr. Rios contributed to the conception of any claim, she (and, through her university's assignment policy, the university) is a co-owner of the entire patent. Under § 262 the university may license Halden's competitor without accounting. Under the joinder rule, Halden cannot sue alone.

Fix. Obtain an assignment or an exclusive license with all substantial rights from the university, plus a covenant to join. Expect the university to want a royalty. If the university refuses, consider whether Dr. Rios was actually an inventor of any claim, and if not, a § 256 correction may be the right path — but only if the analysis is honest, because a correction sought to manufacture standing invites an inequitable conduct counterclaim.

Problem 2: the timing gap. The first inventor's assignment says he "agrees to assign" and was signed three weeks after the invention disclosure.

Analysis. This is Stanford and FilmTec. Halden may hold only an equitable interest. Between Halden and the inventor, specific performance is available. Against a third party who took a present assignment in the interval, Halden could lose.

Fix. Obtain a confirmatory present assignment now, record it, and check whether the inventor executed anything else in the gap (prior employer, consulting client, university). Then fix the form agreement company-wide.

Problem 3: the corporate chain. The patent was originally assigned to "Halden Photonics LLC," which converted to a corporation in 2021.

Analysis. A statutory conversion generally transfers assets by operation of law, and § 261's writing requirement applies to assignments, not to transfers by operation of law. But the record should show it. An unrecorded conversion leaves the USPTO register showing a nonexistent entity as owner, which invites a standing challenge and confuses later purchasers.

Fix. Record the certificate of conversion and a confirmatory assignment.

Problem 4: an old exclusive license. A 2019 agreement granted a distributor an exclusive license in Japan, including the right to sue there.

Analysis. A territorially limited exclusive license generally leaves Halden with all substantial rights in the United States, so U.S. standing is intact. But the agreement must be read for retained enforcement rights, settlement vetoes, and any obligation to share recoveries, and it must be disclosed in litigation.

Total cost of prevention: a present-tense assignment clause signed before day one, an inventorship review at filing, prompt recordation, and a written allocation in the sponsored research agreement. Perhaps four hours of work spread across five years.

Chain-of-title checklist

  • Identify every named inventor and confirm inventorship claim by claim.
  • For each inventor, obtain a present-tense assignment ("hereby assigns"), signed and dated.
  • Confirm each assignment predates or promptly follows conception; obtain confirmatory assignments where it does not.
  • Check each inventor's prior and concurrent obligations (prior employer, university, consulting client).
  • Include further assurances and a power of attorney in every assignment.
  • Include the state statutory carve-out and notice where required (e.g., Cal. Lab. Code §§ 2870, 2872).
  • Address ownership, enforcement, licensing consent, and accounting in every joint development and sponsored research agreement.
  • Record assignments at the USPTO within three months.
  • Record corporate name changes, mergers, and conversions.
  • Perfect security interests by UCC-1 and consider a USPTO filing as well.
  • Check for a government-support clause and pull the Bayh-Dole compliance file if present.
  • Before filing suit, assemble the complete chain and confirm the plaintiff holds all substantial rights or can join the patentee.

Frequently asked questions

Who owns an invention made by our employee? Initially, the employee. The company owns it only through an assignment (preferably present-tense and pre-existing), or, in narrow circumstances, through the hired-to-invent doctrine. Absent both, the company may have only a shop right.

Is inventorship the same as ownership? No. Inventorship is a factual determination about who conceived the claims; ownership is a legal question about who holds title. They start together and diverge the moment an assignment is signed.

Can a co-owner license our competitor? Yes, and without accounting to you, unless your agreement says otherwise. § 262. This is the strongest argument for never leaving joint ownership to the default rule.

Can one co-owner sue alone? Generally no. All co-owners must be joined, and a refusing co-owner can defeat the suit unless it has contractually agreed to join.

We are an exclusive licensee. Can we sue? Only in your own name if you hold all substantial rights, judged on the substance of the agreement rather than its label. Otherwise you must join the patentee. Negotiate for enforcement control and a covenant to join.

Do we have to record assignments? Not to make them effective between the parties, but recordation within three months protects against a later bona fide purchaser under § 261. Record everything material.

What if an inventor refuses to sign? Use the power of attorney in the assignment if you have one. If not, § 118 permits an assignee or a person with a sufficient proprietary interest to file on behalf of a non-signing inventor, and a court can order specific performance of an obligation to assign.

Does federal funding mean the government owns our patent? No. Bayh-Dole leaves title with the contractor that owns the invention, subject to disclosure and election obligations and a government license. Stanford v. Roche. But the obligations are real and the deadlines are unforgiving.

We acquired a company. Do we own its patents? Usually, by operation of law or by the asset assignment in the purchase agreement, but confirm and record. Gaps caused by dissolved intermediate entities are common and are painful to fix later.

How early should we worry about this? Before the first employee starts. The entire class of problems in this article is created by documents that were signed late, drafted in the wrong tense, or never signed at all.

What does a chain-of-title problem actually cost? It varies with when it is found. Found at hiring, it costs a signature. Found in a financing, it costs a disclosure schedule entry and perhaps an escrow. Found in acquisition diligence, it costs a price adjustment and gives the counterparty leverage over the whole deal. Found on the eve of trial, it can cost the case, because the fix requires the cooperation of a person who now knows exactly how much that cooperation is worth.

Closing thought

Patent litigation is expensive enough that the ownership question ought to be settled long before a complaint is drafted. It usually is not, because assignment paperwork is boring, is handled by whoever onboards employees, and produces no visible benefit until the day it produces an enormous one.

Three habits prevent nearly all of it. Use the present tense. Sign before the work starts. Record promptly.

The fourth habit is for the other side of the table: when you are defending a patent case, ask for the chain of title in your first document request. A surprising number of asserted patents have a gap in them, and the party asserting the patent is often the last to know.

Related articles

This article is provided for general informational purposes and does not constitute legal advice. Ownership and standing outcomes depend on specific documents, dates, and state law. Consult qualified patent counsel about any particular portfolio or dispute.