Letters of Consent and Coexistence Agreements: Overcoming Similarity Objections in Mexico

For decades, the Mexican Institute of Industrial Property (IMPI) flatly refused to accept letters of consent. The authority’s position was simple: the will of private parties cannot override the law’s duty to protect consumers from confusion. That changed with the 2018 reform of the Industrial Property Law, and was reinforced by the Federal Law for the Protection of Industrial Property (LFPPI) that came into force on November 5, 2020. Today, letters of consent and coexistence agreements are expressly recognised as valid tools to overcome similarity objections — but their acceptance is not automatic, and applicants must understand both the opportunities and the limits.

The Legal Basis: Article 173, Section XXII

Article 173 of the LFPPI lists the grounds on which a trade mark application may be refused. Section XXII prohibits marks that are identical or confusingly similar to an earlier pending application or valid registration covering the same or similar goods or services. However, the penultimate paragraph of that section provides a critical exception: the prohibition shall not apply where the owner of the earlier right grants express written consent in accordance with the applicable regulations.

This exception covers two scenarios: marks that are confusingly similar applied to the same or similar goods, and marks that are identical applied to similar (but not identical) goods or services. The only situation that remains outside the exception is identical marks for identical goods or services — no consent can overcome that combination.

The Historical Context: Why This Matters

Before 2018, Mexico was an outlier among major trade mark jurisdictions. The USPTO, EUIPO, and most national offices around the world accepted consent letters as strong evidence that coexistence would not cause confusion. IMPI, however, consistently rejected them, reasoning that consumer protection was a matter of public interest that could not be waived by private agreement.

This created significant practical difficulties for multinational companies with related subsidiaries that needed to share a house mark, and for unrelated parties whose marks coexisted peacefully in other markets. The 2018 reform brought Mexico into alignment with international practice, and the LFPPI consolidated this change.

Letter of Consent vs. Coexistence Agreement

Although often used interchangeably, these are distinct instruments:

• Letter of consent: A unilateral document in which the owner of the earlier mark consents to the registration and use of the later mark. It is addressed to IMPI and filed as part of the applicant’s response to an official action.
• Coexistence agreement: A bilateral contract between both parties that sets out the terms and conditions under which the marks will coexist. It typically includes provisions on territorial scope, product differentiation, dispute resolution, and mutual obligations.

Either document can be submitted to IMPI to overcome a similarity objection. A coexistence agreement offers additional benefits: it provides a framework for managing the relationship over time and can include clauses to prevent future opposition or cancellation actions.

What the Document Should Include

A well-drafted letter of consent or coexistence agreement should contain:

• Identification of both marks: The earlier registration (with number) and the pending application (with number) should be clearly specified.
• Express written consent: An unambiguous statement that the earlier mark owner consents to the registration and use of the applicant’s mark in Mexico.
• Specification of goods or services: The consent should indicate which goods or services are covered. Limitations, if any, should be stated clearly.
• Signatory authority: The document must be signed by the proprietor of the earlier mark or an authorised representative with documented authority.
• Legalisation or apostille: If the document is executed abroad, it may require an apostille or consular legalisation to be valid before IMPI.

IMPI’s Discretion: The Practical Reality

Although the LFPPI recognises consent letters, IMPI examiners retain discretion over their acceptance. In practice, IMPI has denied consent letters in certain circumstances, particularly where:

• The marks are identical and the goods or services are also identical — this falls outside the statutory exception.
• There is a risk of trademark dilution, particularly for well-known or famous marks.
• The examiner concludes that consumer confusion is so likely that private consent cannot cure the public interest concern.

This discretion means that obtaining a consent letter does not guarantee registration. Applicants should prepare arguments addressing why coexistence will not mislead consumers, and should consider differentiating the marks or narrowing the goods to strengthen the case.

The Special Case of Related Companies

Historically, IMPI also rejected consent letters between companies in the same corporate group — a particularly frustrating outcome for multinationals. Although the LFPPI now permits consent generally, IMPI’s practice in this area remains inconsistent. Some Circuit Courts have ruled that IMPI must accept coexistence agreements between related enterprises, relying on Article 55 of the Industrial Property Regulations, which defines when companies belong to the same economic group. However, these rulings are not universally binding, and outcomes can vary.

The Procedure

When IMPI issues an official action citing a prior mark as a barrier, the applicant has a two-month term (automatically extendable for a further two months) to respond. During this window, the applicant can negotiate with the earlier mark owner, obtain the consent letter or execute a coexistence agreement, and file it with IMPI along with legal arguments.

Applicants should begin negotiations promptly upon receiving the official action. The two-plus-two-month window is tight for international negotiations involving legalisation formalities.

Strategic Considerations

• Start early: If a pre-filing search reveals a potential conflict, consider approaching the earlier mark owner before filing. Having a consent letter ready can prevent the official action entirely or allow a swift response.
• Use coexistence agreements for long-term protection: A bilateral agreement offers more security than a unilateral consent letter, as it includes mutual commitments and can address future filings in other jurisdictions.
• Differentiate where possible: If the marks are very close, consider visual or specification differences that strengthen the case for coexistence and reduce the risk of IMPI exercising its discretion to refuse.
• Prepare for refusal: If IMPI rejects the consent, the applicant can appeal to the Federal Court of Administrative Affairs (FCAA) or file an amparo suit. Some Circuit Courts have been more receptive to coexistence arguments than IMPI.

Common Mistakes

• Assuming consent is automatic: The law permits consent, but IMPI retains discretion. Build a strong supporting case.
• Submitting an informal or unsigned document: The consent must be in writing, signed by an authorised person, and properly legalised if executed abroad.
• Ignoring the identical-for-identical exclusion: No consent can overcome the objection where both marks and goods are identical.
• Waiting too long to negotiate: The response window is limited. International negotiations and document legalisation take time.

Key Takeaway

The recognition of letters of consent and coexistence agreements since 2018 was one of the most significant modernisations of Mexico’s trade mark system. These instruments bring Mexico closer to international practice and provide a practical path to coexistence. However, IMPI’s discretion and inconsistent application mean that applicants should treat consent as a strong tool, not a guaranteed solution. Professional guidance and early negotiation remain essential.