Trademark Infringement Opinions
Una opinión escrita antes de lanzar, o antes de seguir usando una marca.
Before you launch a name close to another brand, or decide whether to keep using a mark after a demand letter, you need a reasoned answer to one question: is this use likely to infringe or dilute? We prepare written opinions that apply the Eleventh Circuit's likelihood-of-confusion factors and federal and Florida dilution law to your facts, with clear advice on timing, privilege, and who should see the opinion.
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A written answer to one question: is this use likely to infringe or dilute?
An infringement opinion is a letter or memorandum from counsel that applies trademark law to a specific name, logo, slogan, package, or product look, used on specific goods or services, in specific channels. It identifies the marks that pose a risk, works through the likelihood-of-confusion factors one by one, considers dilution where a famous mark is involved, and reaches a stated conclusion with the reasons behind it.
It is different from a search report, which lists what is out there, and from a freedom-to-operate opinion, which clears a new brand across many potential conflicts before launch. An infringement opinion usually starts from a known problem: a competitor's mark you have seen, a cease-and-desist letter you have received, or a launch that resembles an established brand.
An opinion does not make a use lawful, and it does not bind a court. Its value is that it gives decision-makers a reasoned basis for what they do next, and that it can later show the company acted carefully. Both uses depend on the opinion being thorough, based on accurate facts, and obtained before the decision it supports.
When clients ask for one
- Before launching a name, logo, or package close to an existing brand
- After a cease-and-desist letter, before deciding to keep using the mark
- Before a comparative ad, parody, or reference to another company's brand
- When a distributor, retailer, or marketplace asks for assurance
- When a Latin American or European brand enters the U.S. under a name already used here
- When a board or investor wants the risk in writing before committing funds
Launch, continue, or defend: what an opinion is for
The same analysis serves three different decisions. Knowing which one you face shapes how the opinion is written and who should see it.
Deciding whether to launch
A clear view of the risk before money goes into packaging, inventory, and advertising. If the risk is high, the opinion explains what changes would lower it: a different word, a different design, or a narrower product line.
Business decisionDeciding whether to keep going
After a demand, continuing to use a mark is a choice made with notice of the other side's claim. An opinion tests the letter's claim and the strength of your defenses, so the choice to continue, modify, phase out, or negotiate rests on analysis rather than instinct.
Post-notice conductShowing good faith
Willfulness and intent matter to money. A defendant's mental state is "a highly important consideration" for a profits award (Romag, 2020), and it bears on enhanced damages and on whether a case is exceptional enough for fees. A careful, timely opinion is evidence of good faith.
15 U.S.C. § 1117(a)The reverse is also true. In Frehling Enterprises v. International Select Group (11th Cir. 1999), the court counted the defendant's failure to run a trademark search, and its continued use after the USPTO refused registration for likely confusion, as evidence of improper intent. See Damages Evaluations for how intent changes the numbers.
Seven factors, two that weigh most
Federal courts in Florida, Georgia, and Alabama apply the Eleventh Circuit's seven likelihood-of-confusion factors. In Frehling the court said that "the type of mark and the evidence of actual confusion are the most important." No factor is decisive, and the court weighs them together.
| # | Factor | What we look at | Typical evidence |
|---|---|---|---|
| 1 | Type (strength) of the mark Weighs most | Where the senior mark sits on the scale from generic, descriptive, and suggestive to arbitrary or fanciful, and how much third-party use weakens it | Registrations, dictionary meaning, third-party marks in the field, advertising and sales |
| 2 | Similarity of the marks | Overall appearance, sound, meaning, and commercial impression, including translations | Side-by-side comparisons, how the marks appear in use |
| 3 | Similarity of the products | Whether consumers would expect the goods or services to come from one source | Product lines, brand extensions in the industry |
| 4 | Retail outlets and customers | Overlap in where and to whom the products are sold | Distribution lists, marketplace listings, customer profiles |
| 5 | Advertising media | Overlap in how each party promotes its products | Ad spend, social media, trade shows, search terms |
| 6 | Defendant's intent | Whether the junior user meant to benefit from the senior mark's reputation, or was willfully blind to it | Adoption history, searches run, internal emails, response to notice |
| 7 | Actual confusion Weighs most | Real instances of confusion among customers, and whether they matter in context | Misdirected calls, emails, reviews, returns; consumer surveys |
The USPTO and the Trademark Trial and Appeal Board apply a different list, the du Pont factors, when deciding whether a mark can be registered. An opinion about use in the marketplace applies the court test; we flag where a registration question would come out differently. Where a dispute may be filed outside the Eleventh Circuit, such as in New York or Illinois, we note how that circuit's factors differ.
Dilution is a separate question, and only famous marks qualify
Dilution protects a famous mark even without confusion or competition. Because the bar for fame is high, most opinions conclude that federal dilution is not in play. When it is, the analysis is different from infringement.
The mark must be "widely recognized by the general consuming public of the United States" as a source. Fame in a niche market is not enough. Courts consider advertising reach, sales, actual recognition, and federal registration.
Dilution is actionable regardless of actual or likely confusion, competition, or actual economic injury. The question is whether the use is likely to blur or tarnish the famous mark.
Similarity, the famous mark's distinctiveness, its exclusivity, its recognition, any intent to create an association, and any actual association.
Fair use, including comparative advertising and parody or commentary, but only when the use is not "a designation of source" for the user's own goods; news reporting; and noncommercial use.
An injunction is available on proof of dilution. Profits and damages require use first begun after October 6, 2006, and willful intent to trade on the famous mark or harm its reputation, which is where an opinion matters.
Florida protects marks "famous in this state." Relief is generally an injunction; other Chapter 495 remedies require willful intent and a Florida registration. See Florida Trademark Dilution.
The federal standard was set by the Trademark Dilution Revision Act of 2006, signed October 6, 2006, which replaced the actual-dilution requirement of Moseley v. V Secret Catalogue with a likelihood-of-dilution standard. That is why the October 6, 2006 date appears in the remedies provision. For contested cases, see Trademark Dilution Litigation.
After Jack Daniel's, a joke used as a brand gets no special pass
For years, some courts screened out claims against expressive works under the Rogers v. Grimaldi test, which asked only whether the use had artistic relevance and was not explicitly misleading. In Jack Daniel's Properties, Inc. v. VIP Products LLC (June 8, 2023), a unanimous Supreme Court held that the Rogers threshold does not apply when the accused party uses the mark as a designation of source for its own goods. The "Bad Spaniels" dog toy was used as a trademark, so the ordinary likelihood-of-confusion analysis applied.
The Court also held that the Lanham Act's noncommercial-use exclusion does not shield parody, criticism, or commentary from a dilution claim when the parody is used as a source identifier. The fair-use exclusion for parody already carves out source-identifying uses, and the Court would not let the noncommercial exclusion swallow that limit.
Parody still counts. The Court noted that a parody may make a difference within the standard confusion analysis, because consumers who get the joke may be less likely to think the brand owner is behind it. An opinion on a parody product, a humorous merchandise line, or a "lookalike" package now has to assess confusion directly, and cannot rely on a threshold test to end the inquiry.
Questions an opinion asks about a parody
- Is the other brand's mark used as our name, logo, or trade dress?
- Does the product comment on the original, or just borrow its fame?
- Is the target mark famous, so that dilution is in play?
- Would buyers see the joke at the point of sale, including online thumbnails?
- Does packaging disclaim affiliation clearly and prominently?
- Is the use in a title or work of art rather than as a brand?
Relying on an opinion in court can open your files
An opinion is privileged legal advice until you use it as evidence. Once a company tells a court "we acted in good faith because our lawyers said so," the other side is entitled to test that claim, which can mean access to more than the opinion itself.
The patent rule is the most developed. In In re EchoStar Communications Corp., 448 F.3d 1294 (Fed. Cir. 2006), the Federal Circuit held that a party relying on advice of counsel to defend against willful patent infringement waives privilege over communications with counsel on the same subject, and over work product that was communicated to the client or that reflects those communications. Work product never shared with the client stayed protected, because it could not have shaped the client's state of mind. Patent law also has a statute, 35 U.S.C. § 298, under which failing to obtain an opinion cannot be used to prove willful patent infringement.
Trademark cases are different. EchoStar is Federal Circuit patent law, and § 298 applies only to patents. Trademark cases are decided under the privilege law of the regional circuit, and there is no trademark equivalent of § 298. In the Eleventh Circuit, Cox v. Administrator U.S. Steel & Carnegie, 17 F.3d 1386 (11th Cir. 1994), holds that a party who affirmatively asserts its good-faith belief in the lawfulness of its conduct can put its legal advice at issue and waive privilege. How far that waiver reaches in a trademark case is less settled than in patent law, so we plan as if it could cover the whole subject matter of the opinion.
The practical consequences: decide early whether an opinion is meant to guide the business privately or to be used as evidence later; keep the opinion separate from trial strategy; and limit distribution to the people who make the decision.
Keep it privileged: limit circulation, label it, and do not share it with customers, distributors, or the other side.
Assume everything on the subject could be produced. A separate opinion counsel, distinct from litigation counsel, can help keep trial strategy out of the waiver.
An opinion dated after launch, or long after a demand letter, says little about your state of mind when you chose to proceed.
An opinion built on incomplete or inaccurate facts can backfire, because it shows what you knew and chose not to share.
Ignoring a negative opinion, or its conditions, is worse than having no opinion at all.
The structure of a written infringement opinion
Each opinion is written for the decision at hand, but the core structure is consistent so that a reader, including a judge years later, can follow the reasoning.
Question and scope
The exact mark, goods or services, channels, and territory covered, and what is outside the opinion.
Facts and assumptions
The facts we relied on, their source, and the assumptions that, if wrong, would change the conclusion.
Marks of concern
The registrations and common-law uses that matter, their status, owners, and strength, drawn from searching.
Factor-by-factor analysis
Each of the seven Eleventh Circuit factors applied to the evidence, with the weight given to each.
Dilution and other claims
Federal and Florida dilution where fame is plausible; false designation, trade dress, and FDUTPA where relevant.
Defenses
Prior use, descriptive and nominative fair use, laches, invalidity, and abandonment of the other mark.
Conclusion and risk level
A stated conclusion on likelihood of infringement or dilution, and an overall risk level with reasons.
Options
Changes that would lower risk, coexistence or consent approaches, and what to monitor after launch.
Quick search, infringement opinion, or freedom to operate
These three services answer different questions at different costs. Many clients start with a quick search and move up only if it turns up a problem.
| Quick knockout search | Infringement opinion | Freedom-to-operate opinion | |
|---|---|---|---|
| Question answered | Is there an obvious conflict in the USPTO records? | Is this specific use likely to infringe or dilute a specific mark? | Is this new brand clear to launch in the target markets? |
| Starting point | A proposed name | A known mark, letter, or close resemblance | A proposed name, logo, package, or product look |
| Searching | Federal records, identical and close marks | Focused on the marks of concern, plus their use and strength | Full federal, state, common-law, domain, marketplace, and foreign searching |
| Analysis | Short screening comments | Seven-factor confusion analysis, dilution, defenses | Risk assessment across all conflicts found, including trade dress |
| Deliverable | Email or short report | Written opinion with a stated conclusion | Written risk assessment with options |
| Use as evidence of good faith | Limited | Designed for it, with privilege trade-offs | Supports good faith at adoption |
| Learn more | Federal Trademark Applications | This page | Freedom to Operate |
How we prepare an infringement opinion
Opinions are prepared by Robert Thornburg, who prepares written clearance and freedom-to-operate opinions and litigates Lanham Act cases, with Susan Latham where advertising or litigation issues are central. We work in English and Spanish, and use qualified translators for marks and evidence in Portuguese, French, German, or Italian.
- IntakeConflict check and scopeWe confirm we can act, then define the question, the mark, and the decision it supports.
- FactsGather the recordYour adoption history, use, channels, and any letter, plus the other side's registrations and use.
- ResearchInvestigate the other markStatus, scope of use, third-party marks in the field, and evidence of strength or weakness.
- AnalysisApply the lawConfusion factors, dilution, defenses, and how a court in the likely forum would weigh them.
- DeliveryWritten opinion and callWe walk decision-makers through the conclusion, the options, and who should receive it.
What we need from you
- Images of your mark, packaging, and product as actually used or planned
- The goods and services, price points, and sales channels, including marketplaces
- How and when you chose the name, and any searches already run
- Any cease-and-desist letter, demand, or marketplace complaint, with dates
- Any reports of confusion, such as misdirected inquiries or reviews
- Your launch or decision date, and who will rely on the opinion
Five most common mistakes with infringement opinions
An opinion helps only if it is obtained, written, and used the right way.
Getting the opinion after the decision
An opinion requested months after launch, or only after a lawsuit is filed, does little to show the state of mind behind the original choice.
TimingAsk before you launch, or promptly after a demand, and before deciding to continue.
Giving counsel a partial picture
Leaving out an earlier search hit, a confusion report, or the real product mockup undermines the opinion and can be used against you.
AccuracyShare everything, including the facts that worry you.
Circulating the opinion widely
Sending the opinion to customers, distributors, or the other side can waive privilege, and an at-issue waiver can reach more than the document itself.
PrivilegeDecide the audience at the start and keep distribution tight.
Relying on parody or "it's just a joke"
After Jack Daniel's, a parody used as a brand gets the full confusion analysis and may face dilution claims.
Jack Daniel's (2023)Test a parody product the same way you would test any other brand.
Ignoring the opinion's conditions
Opinions often depend on changes, such as a different color, a disclaimer, or staying out of a channel. Proceeding without them removes the opinion's support.
Follow-throughTreat the conditions as part of the launch plan, and update the opinion if the facts change.
Frequently asked questions
Is an infringement opinion required by law?
No. There is no legal duty to obtain one. But intent bears on profits, enhanced damages, and fees, and courts have treated a failure to search before adopting a mark as evidence of improper intent. An opinion is a way to make, and document, a careful decision.
Will a favorable opinion stop a lawsuit?
No. It does not bind the other side or a court. It informs your decision and can be evidence of good faith if your intent is later questioned. We do not predict outcomes; we explain risk and options.
If I rely on the opinion in court, will I lose privilege?
Likely as to the opinion, and possibly as to other communications on the same subject. In patent cases In re EchoStar (Fed. Cir. 2006) defines the scope; trademark cases apply regional circuit law, and in the Eleventh Circuit asserting good faith based on legal advice can put that advice at issue. Plan for a broad waiver.
Can the opinion cover dilution as well as infringement?
Yes, when the other mark is plausibly famous. Federal dilution requires recognition by the general consuming public of the United States; Florida dilution requires fame in Florida. Money damages for federal dilution require willful intent.
Does Jack Daniel's mean parody products are always infringing?
No. It means a parody used as a brand gets the ordinary likelihood-of-confusion analysis, not a threshold pass under Rogers. Parody can still weigh against confusion if consumers get the joke.
We received a cease-and-desist letter. Should we get an opinion before responding?
Often, yes, especially if you plan to keep using the mark. Note any deadline in the letter and contact us before it passes. See Responding to a Cease and Desist.
How is this different from a freedom-to-operate opinion?
An infringement opinion focuses on a specific known mark or claim. A freedom-to-operate opinion clears a new brand broadly across federal, state, common-law, online, and foreign conflicts before launch.
Can you write the opinion in Spanish?
Our attorneys work in English and Spanish, so we can discuss and explain the opinion in Spanish. For evidence or marks in Portuguese, French, German, or Italian, we use qualified translators.
Request an opinion
Send images of your mark and product, the other brand you are concerned about, and any letter you received. Tell us the decision you face and when.
- Apply the Eleventh Circuit factors to your facts
- Assess federal and Florida dilution
- Advise on timing, audience, and privilege
- Offer options to lower risk before launch
Prefer to talk first? Call or email, or message us on WhatsApp. Atendemos en español.
- Frehling Enterprises v. International Select Group (11th Cir. 1999)
- 15 U.S.C. § 1125, including dilution under § 1125(c) (Cornell LII)
- 15 U.S.C. § 1117, Recovery for violation of rights (Office of the Law Revision Counsel)
- Jack Daniel's Properties, Inc. v. VIP Products LLC, No. 22-148 (U.S. June 8, 2023)
- Romag Fasteners, Inc. v. Fossil, Inc. (2020), summary (Loeb & Loeb)
- The Scope of the Privilege Waiver Post-EchoStar (WilmerHale)
- 35 U.S.C. § 298, Advice of counsel (Harness IP, AIA text)
- Good-faith defenses and at-issue waiver, discussing Cox v. Administrator U.S. Steel & Carnegie (Buchanan Ingersoll & Rooney)
- Trademark Dilution Revision Act of 2006 (Loeb & Loeb)
- Fla. Stat. § 495.151, Dilution (Florida Senate, 2026)
General information, not legal advice for your situation. Statutes, rules, and fees as of October 2026. Last reviewed October 28, 2026.