Intellectual Property Rights - Law and Practice · Business Concerns in Commercializing Intellectual Property Rights

Rights of Co-owners of Patents under Section 50

Updated 11 October 2026 · Fact-checked

Section 50 of the Patents Act, 1970 governs a patent granted to two or more persons. Unless they agree otherwise, each holds an equal undivided share and may work the invention for his own benefit without accounting to the others. But no licence can be granted, and no share assigned, without the others' consent.

Understand Rights of Co-owners of Patents

A patent can be granted to more than one person, for example two companies that developed an invention together. Section 50 lays down how these co-owners relate to each other. It applies where persons are registered as grantee or proprietor.

The starting point is agreement. Sub-sections (1) to (3) of section 50 are subject to agreement. Sub-sections (1) and (2) say "unless an agreement to the contrary is in force", and sub-section (3) says "any agreement for the time being in force". Sub-sections (4) to (6) are not framed that way. If the co-owners have signed a joint ownership or development agreement, that agreement comes first. Section 50 fills the gaps when there is none.

The Act gives co-owners two different kinds of freedom. Working the invention is free: each co-owner may exercise the rights conferred by section 48, by himself or through agents, for his own benefit, without accounting to the others. So no co-owner has to share profits from his own use. But dealing with the patent is restricted: a licence cannot be granted and a share cannot be assigned by one co-owner except with the consent of the other or others.

The Act also protects outsiders. If one co-owner sells a patented article, the buyer and anyone claiming through him can deal with the article as if it had been sold by a sole patentee. A buyer need not check the other co-owners' consent for an ordinary sale of the product.

If co-owners deadlock, section 51 lets the Controller give directions on application. Section 70 adds that registered owners have the power to assign, license or deal with the patent, but subject to the co-ownership provisions.

Key rules to remember

Equal share (s 50(1)): Patent granted to two or more persons → equal undivided shares, unless an agreement to the contrary is in force; Shares are equal even if contributions to the invention were unequal, unless they agreed otherwise.
Right to work (s 50(2)): Each registered co-owner may exercise the s 48 rights for his own benefit, by himself or his agents, without accounting to the others (unless agreed otherwise); Subject to sections 50 and 51. No duty to share profits from own working.
Consent rule (s 50(3)): No licence and no assignment of a share by one co-owner except with the consent of the other co-owner(s); Subject to sections 50 and 51 and any agreement in force.
Sale of article (s 50(4)): Article sold by one co-owner → buyer and those claiming through him deal with it as if sold by a sole patentee; Protects purchasers of the product.
Movable property rules (s 50(5)): Law on ownership and devolution of movable property applies to patents; trustees' and legal representatives' mutual rights are not affected; Sub-sections (1) and (2) do not disturb those rights.
Controller's directions (s 51): On application by a co-owner, the Controller may direct on sale or lease of the patent, grant of licences, or exercise of s 50 rights, after hearing the others; If a co-owner fails to sign an instrument within 14 days of written request, the Controller may empower another person to sign for him. Directions cannot be inconsistent with an agreement between the co-owners.

How to solve Rights of Co-owners of Patents questions

Use this order for any problem on co-owners of a patent.

1Confirm the patent is registered in the names of two or more persons. Section 50 applies to registered co-owners.
2Check for an agreement between the co-owners. If one exists and covers the issue, it prevails over the default rule.
3Identify the act in question: working the invention, granting a licence, assigning a share, or selling the patented article.
4Apply the matching rule. Working: free, no accounting. Licence or assignment: consent of the others needed. Sale of article: buyer treated as buying from a sole patentee.
5If the facts show a deadlock or refusal, bring in section 51: application to the Controller, hearing of the other co-owners, directions, and the 14-day rule for signing instruments.
6Check for trustees or legal representatives of a deceased person. Their mutual rights are saved by section 50(5) and section 51(4).
7State a clear conclusion and, where asked, a practical drafting point such as a joint ownership agreement.

Quickest way: Work, Consent, Buyer test

When to use it: Use for short-answer or case questions where you must say quickly what a co-owner may do.

Is there an agreement? If yes, follow it.
Working the invention himself? Allowed, no accounting.
Licensing or assigning a share? Needs the others' consent.
Selling the patented article? Buyer is safe.
Dispute? Controller under section 51.

Common mistakes in Rights of Co-owners of Patents

Saying a co-owner may grant a licence alone because he has an equal share.
Students link the freedom to work the patent with the freedom to license.
Fix: Remember that section 50(3) requires consent of the other co-owners for any licence or assignment of a share, unless an agreement says otherwise.
Saying a co-owner must share profits from his own working of the invention.
Students assume co-ownership always means profit sharing.
Fix: Section 50(2) says he may work it for his own benefit without accounting, unless there is an agreement to the contrary.
Ignoring the agreement between co-owners.
Students memorise the default rules and forget the opening words.
Fix: Always state that the rules apply unless an agreement to the contrary is in force, and check the facts for one.
Saying the buyer of a patented article needs the consent of all co-owners.
Confusing sale of the product with assignment of the patent share.
Fix: Under section 50(4) a purchaser from one co-owner deals with the article as if bought from a sole patentee.
Thinking the Controller can override any agreement between co-owners.
Students remember section 51 as a general dispute power.
Fix: Section 51(4) bars directions that are inconsistent with the terms of an agreement between the registered owners. Separately, section 51(3) requires the Controller to give the other side an opportunity to be heard before giving directions.
Stating that shares are in proportion to contribution.
Students apply partnership-style logic.
Fix: Section 50(1) gives equal undivided shares unless an agreement provides otherwise.

Worked examples

Example 1

Aarav Pharma Ltd and Bhavya Labs Pvt Ltd are registered joint patentees of a process patent. There is no agreement between them. Aarav Pharma manufactures the product using the process and keeps all profits. It also grants a licence to Kiran Industries without telling Bhavya Labs. Advise on the position.

Show the solution

Provision: section 50. Both are registered co-owners, and there is no agreement to the contrary, so the default rules apply.
Working: under section 50(2), each co-owner may exercise the section 48 rights for his own benefit without accounting to the others. Aarav Pharma need not share the profits of its own manufacture with Bhavya Labs.
Licence: under section 50(3), a licence cannot be granted by one co-owner except with the consent of the other. Bhavya Labs did not consent.
Conclusion on the licence: the grant of licence to Kiran Industries is not in accordance with section 50(3).
Remedy and practice: Bhavya Labs may object. If the parties want to license jointly, either may apply to the Controller under section 51, and the Controller will hear the other before giving directions. A joint ownership agreement should settle licensing terms.

Answer: Aarav Pharma may work the patent and keep its profits without accounting, but it could not license Kiran Industries without Bhavya Labs's consent under section 50(3).

Example 2

Meera Textiles and Rohan Dyes are registered co-owners of a patent for a dye. Rohan Dyes sells a quantity of the patented dye to Suresh Traders, who resells it. Meera Textiles says Suresh Traders needed its consent. Is this correct? Also, Rohan Dyes wants to assign its share to another company and Meera Textiles refuses consent. What can Rohan Dyes do?

Show the solution

Sale of the article: section 50(4) provides that where a patented article is sold by one co-owner, the purchaser and any person claiming through him may deal with the article as if sold by a sole patentee.
Application: Suresh Traders, and anyone claiming through it, may resell the dye. Meera Textiles's objection fails.
Assignment of share: section 50(3) requires the consent of the other co-owner for assignment of a share, subject to sections 50 and 51 and any agreement in force. Without Meera Textiles's consent, Rohan Dyes cannot simply assign its share.
Deadlock: Rohan Dyes may apply to the Controller under section 51(1) for directions on the sale of its interest in the patent. The Controller gives such directions as he thinks fit, so the outcome is in his discretion. Meera Textiles must be given an opportunity to be heard under section 51(3).
Limit: the Controller cannot give a direction that is inconsistent with the terms of any agreement between the co-owners, section 51(4).

Answer: Meera Textiles is wrong about the sale, since section 50(4) protects the buyer. Rohan Dyes cannot assign its share without Meera Textiles's consent under section 50(3). It may apply to the Controller under section 51(1) for directions on the sale of its interest, after Meera Textiles is heard. The directions are at the Controller's discretion and cannot be inconsistent with any agreement between the co-owners (section 51(4)).

Exam tips

Begin every answer with the phrase "unless an agreement to the contrary is in force" and then give the default rule.
Separate the three acts clearly: working, licensing or assigning, and selling the article. Examiners often test the contrast.
Quote section numbers only where sure: 50 for co-owners, 51 for Controller's directions, 70 for power to deal.
In case questions, end with a practical point: a joint ownership agreement, written request, or application to the Controller.
Mention the 14-day written request rule in section 51(2) when facts involve a co-owner refusing to sign documents.

Practice questions from Business Concerns in Commercializing Intellectual Property Rights

Rights of Co-owners of Patents in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

CS ExecutiveRights, Ownership and Co-owners of Patents

Rights of Co-owners of Patents: frequently asked questions

Can one co-owner of a patent use the invention without the others' permission?

Yes. Under section 50(2), each registered co-owner may exercise the section 48 rights for his own benefit, by himself or his agents. He need not account to the other co-owners, unless an agreement says otherwise.

Can a co-owner license or assign his share alone?

No. Section 50(3) says a licence cannot be granted and a share cannot be assigned by one co-owner except with the consent of the other co-owner or owners. An agreement between them may change this.

What happens if co-owners cannot agree?

Any of them can apply to the Controller under section 51. The Controller gives directions on sale or lease of the patent, licences, or exercise of section 50 rights, after giving the others a hearing. The directions cannot conflict with their agreement.

Are the shares of co-owners equal?

Yes, by default. Section 50(1) gives each co-owner an equal undivided share unless an agreement to the contrary is in force.