DuPont Factors Explained: Winning Likelihood-of-Confusion Trademark Refusals

Introduction

When the United States Patent and Trademark Office (USPTO) examines a trademark application or when courts evaluate potential trademark infringement, the fundamental question is whether consumers are likely to be confused about the source of goods or services. This determination isn't based on guesswork or simple side-by-side comparison—it's guided by a sophisticated analytical framework established in the landmark 1973 case In re E.I. du Pont de Nemours & Co., 476 F.2d 1357 (CCPA 1973).

The DuPont factors provide a comprehensive, thirteen-point framework for assessing likelihood of confusion. These factors apply in both ex parte trademark examinations at the USPTO and inter partes proceedings before the Trademark Trial and Appeal Board (TTAB), as well as in federal court trademark infringement litigation. Understanding these factors—and how examining attorneys, the TTAB, and federal courts apply them—is essential for anyone involved in trademark strategy, prosecution, or litigation.

The Complete List of 13 DuPont Factors

The thirteen DuPont factors established by the Court of Customs and Patent Appeals are:

1. Similarity or dissimilarity of the marks in their entireties as to appearance, sound, connotation, and commercial impression
2. Similarity or dissimilarity and nature of the goods or services described in an application or registration or in connection with which a prior mark is in use
3. Similarity or dissimilarity of established, likely-to-continue trade channels
4. Conditions under which and buyers to whom sales are made (i.e., "impulse" vs. careful, sophisticated purchasing)
5. Fame of the prior mark (sales, advertising, length of use)
6. Number and nature of similar marks in use on similar goods
7. Nature and extent of any actual confusion
8. Length of time during and conditions under which there has been concurrent use without evidence of actual confusion
9. Variety of goods on which a mark is or is not used
10. Market interface between the applicant and the owner of a prior mark, including:
    • A mere "consent" to register or use
    • Agreement provisions designed to preclude confusion
    • Assignment of mark, application, registration and goodwill
    • Laches and estoppel attributable to owner of prior mark
11. Extent to which applicant has a right to exclude others from use of its mark on its goods
12. Extent of potential confusion (i.e., whether de minimis or substantial)
13. Any other established fact probative of the effect of use

Are All Factors Given Equal Weight?

No. The DuPont case itself stated that not all factors are given equal weight, and one factor may be more controlling than others depending on the particular case. The weight given to factors varies considerably based on the specific facts of each case.

The Two Most Important Factors

The first two factors—similarity of the marks and similarity/relatedness of the goods or services—consistently carry the most weight in likelihood of confusion analyses. As the USPTO's Trademark Manual of Examining Procedure (TMEP) makes clear, these are "key considerations in any likelihood of confusion determination."

In the vast majority of cases, these first two factors perform most or all of the analytical work. The Federal Circuit has repeatedly emphasized their importance, noting that the TTAB should weigh the similarity of marks heavily when they are highly similar, particularly when lead words "look and sound almost the same and have the same connotation and commercial impression."

The Sliding Scale Between Factors 1 and 2

Courts and the USPTO apply a sliding scale between the first two factors:

• If marks are highly similar, the goods or services do not need to be as closely related to find likelihood of confusion
• If goods or services are identical or closely related, the marks do not need to be as similar to find likelihood of confusion

This sliding scale recognizes that strong similarity in one factor can compensate for weaker similarity in the other when assessing overall likelihood of confusion.

Fame Can Be Dispositive

The fifth factor—fame of the prior mark—can be particularly powerful. A famous mark is entitled to broader protection against even dissimilar marks or distantly related goods. As several courts have noted, a prior mark's fame, on its own, could lead to a finding of likelihood of confusion even if other factors would indicate otherwise.

However, fame exists on a spectrum from strong to weak—it's not a binary yes/no question as it would be in a dilution analysis. The Federal Circuit has criticized the TTAB for treating fame too narrowly and reminded the Board that even marks that fall "somewhere in the middle" of the fame spectrum deserve appropriate weight.

Must All Factors Be Considered?

Yes, if there is record evidence. The Federal Circuit has been clear and emphatic on this point: when analyzing whether a likelihood of confusion exists between two marks, the TTAB must consider all likelihood-of-confusion factors for which there is record evidence.

This principle was reinforced in the 2019 case In re Guild Mortgage Company, where the Federal Circuit reversed the TTAB's decision specifically because the Board failed to address the eighth factor (concurrent use without confusion) despite record evidence addressing it. The applicant had submitted a declaration from its President and CEO stating that Guild Mortgage and Guild Investment Management had coexisted in the same geographic market (Southern California) for over forty years without any evidence of actual confusion.

The Federal Circuit held that although the Board stated it had considered the factors for which there was argument and evidence, its failure to even mention the eighth factor, much less address the argument and evidence directed to it, was reversible error—not harmless error. The Court did not prescribe what weight should be given to the evidence, but made clear that it was error not to consider it at all.

Not All Factors Are Always Relevant

While the TTAB must consider all factors for which there is record evidence, not all factors are relevant in every case. Some factors may be neutral or have no evidentiary record. For example:

• If there's no evidence of actual confusion or concurrent use, factors 7 and 8 may be neutral
• If the prior mark isn't famous, factor 5 may not weigh heavily
• If there are no similar third-party marks on similar goods, factor 6 may not support either side

The key is that parties cannot win simply by ignoring factors that don't favor them—if record evidence exists, it must be addressed.

How to Demonstrate Proof for Each Factor

Understanding how to prove each factor is critical for both trademark applicants seeking registration and opposers seeking to block registration or prove infringement.

Factor 1: Similarity of the Marks

What's Analyzed: Appearance, sound, connotation, and commercial impression of the marks in their entireties.

How to Prove:

• For similarity: Show visual, phonetic, or conceptual similarities; demonstrate that dominant elements are identical or nearly identical
• Against similarity: Emphasize differences in overall commercial impression; show distinguishing elements; prove marks create different impressions in context

Key Points:

• Marks must be compared in their entireties, though one element may be given more weight if it's the dominant or distinctive feature
• Commercial impression matters more than isolated elements
• For standard character marks, all reasonable depictions must be considered, not just "reasonable" ones
• Marks are assessed "through the eyes of the consumer" based on how they're actually used in commerce

Common Arguments:

• For Confusion: Lead words are identical; overall sound and appearance are similar; marks share dominant elements; addition of generic/descriptive terms doesn't distinguish marks
• Against Confusion: Marks create different overall commercial impressions; substantial visual differences; different meanings or connotations; additional elements significantly alter perception

Factor 2: Similarity of Goods or Services

What's Analyzed: Whether goods or services are identical, related, complementary, or likely to be encountered by the same consumers.

How to Prove:

• For relatedness: Third-party registrations showing both types of goods/services; evidence that goods are complementary or consumed together; dictionary definitions showing overlap; evidence of common trade channels; proof that goods serve similar functions
• Against relatedness: Show goods are completely unrelated; demonstrate different consumer bases; prove distinct methods of manufacture; evidence of different distribution channels

Key Points:

• ABSOLUTELY CRITICAL - THE MOST IMPORTANT RULE FOR FACTOR 2: The TTAB analysis is based ENTIRELY on the identifications of goods/services in the application and registration, NOT on how parties actually use their marks in the marketplace or "real-world conditions"
• This is mandated by Federal Circuit precedent in Stone Lion Capital (2014) and Octocom Systems v. Houston Computer Services (1990)
• "Parties that choose to recite services in their trademark application that exceed their actual services will be held to the broader scope of the application" (Stone Lion, 746 F.3d at 1326)
• An application with no restrictions on trade channels or classes of consumers cannot be narrowed by testimony about actual use
• The TTAB "is not required to review real world conditions" and its focus must be "on the trademark application and registered marks at issue rather than on 'real-world conditions'" (Stone Lion)
• Why this rule exists: Because the benefits of registration (nationwide constructive notice, presumption of validity, right to sue for infringement) are "commensurate with the scope of the services recited in the application, not with the applicant's then-existing services"
• Practical implication: Broad identifications create broad potential for conflict. If you identify services as "financial services," you'll be held to that full scope even if you only provide mortgage banking
• Goods need not be identical—"related" or "complementary" is sufficient
• If goods move in the same channels and are purchased by the same consumers, they may be found related even if different in nature
• Courts have found relatedness between: cigars and wine, skin care and makeup, credit cards and banking services, tea products and toiletries
• When goods are "legally identical" (when the identification in one encompasses the identification in the other), similarity of goods weighs heavily in favor of confusion

TTAB vs. Federal Court Distinction:

At the TTAB: Analysis is strictly limited to the identifications in the application and registration. Real-world evidence of how you actually use your mark is irrelevant.

In Federal Court (infringement litigation): Courts CAN and DO consider actual marketplace conditions, actual customers, how marks are actually used, and real-world evidence. This is a major procedural advantage in litigation.

Common Arguments:

• For Confusion: Goods are complementary; sold in same stores; marketed to same consumers; used together; serve similar purposes; within same general industry; identifications overlap or are legally identical
• Against Confusion: Fundamentally different products under the plain language of the identifications; different price points (as reflected in identification); different channels of trade (as identified); different consumer demographics (as identified); manufactured differently; narrow your identification to limit scope
• Critical Strategy: When filing an application, carefully craft your identification to be as narrow as necessary to cover your actual and planned use, but no broader—overly broad identifications will come back to haunt you in ex parte examination

Factor 3: Similarity of Trade Channels

What's Analyzed: Whether goods travel through the same distribution channels and are sold to the same classes of consumers.

How to Prove:

• For similarity: Evidence showing both parties sell through retail stores, online platforms, or specialty outlets; proof of overlap in distribution networks; evidence from trade publications showing industry overlap
• Against similarity: Show completely different distribution methods (e.g., wholesale vs. retail; medical vs. consumer); prove distinct sales channels with no overlap

Key Points:

• Like Factor 2, this is analyzed based on the application/registration language, not actual marketplace conditions
• The TTAB "is not required to review real world conditions" (Stone Lion)
• If the identifications have no restrictions on trade channels, the TTAB will presume the goods/services could travel in all normal channels for those types of goods/services
• Overlap in trade channels strongly suggests likelihood of confusion
• Even sophisticated purchasers in specialized channels can be confused if marks are similar
• When goods/services are legally identical or highly related, courts typically find trade channels are the same or substantially overlap

Factor 4: Conditions of Sale and Sophistication of Purchasers

What's Analyzed: Whether purchases are impulse buys or careful, considered decisions; the sophistication level of consumers.

How to Prove:

• For carefulness: High price points; complexity of products; evidence that consumers conduct research; industry requiring specialized knowledge
• For impulse/lack of sophistication: Low-cost items; everyday consumer goods; evidence of impulse purchases; mass-market appeal

Key Points:

• CRITICAL: The analysis focuses on the sophistication of ALL POTENTIAL PURCHASERS based on the identification of goods/services, not just actual customers
• Even if you only sell to sophisticated Fortune 500 companies, if your identification covers services that could be sold to unsophisticated consumers, the TTAB will analyze based on the least sophisticated potential purchasers
• As the Federal Circuit held in Stone Lion: "Although recognizing that Stone Lion and Lion in fact require large minimum investments and target sophisticated investors, the Board focused on the sophistication of all potential customers of 'the parties' services as they are recited in the application and registrations, respectively'"
• Board precedent requires the decision to be based "on the least sophisticated potential purchasers" (General Mills v. Fage Dairy)
• Expensive doesn't always mean sophisticated: Courts have held that even relatively expensive purchases may not involve sophisticated consumers if the products are mass-market
• Even sophisticated purchasers can be confused by similar marks
• This factor rarely outweighs strong similarity in marks and goods
• An application with no restrictions on classes of consumers cannot be narrowed by testimony about actual sophisticated customers

Common Arguments:

• For Confusion: Products are inexpensive; mass-market goods; consumers don't exercise care in purchasing; identification encompasses ordinary consumers
• Against Confusion: High-price items; complex technical products; specialized professional services; lengthy purchase decision process; sophisticated business customers; narrow your identification to specify that services are only provided to sophisticated purchasers (e.g., "investment advisory services for institutional investors with minimum investments of $10 million")

Factor 5: Fame of the Prior Mark

What's Analyzed: The degree of recognition the prior mark has achieved in the marketplace, on a spectrum from weak to famous.

How to Prove:

• Sales figures and revenue
• Advertising expenditures and reach
• Length and continuous use of mark
• Unsolicited media coverage and awards
• Market share data
• Consumer surveys showing recognition
• Evidence of intentional copying
• Third-party references to the mark

Key Points:

• Fame is assessed on a spectrum, NOT as binary yes/no
• The standard for "fame" under DuPont is lower than the stringent standard required for dilution claims under the Lanham Act
• Even marks with moderate recognition may receive enhanced protection
• Famous marks are entitled to protection against use on dissimilar goods

Common Arguments:

• For Confusion: Extensive advertising spending; long history of use; high consumer recognition; market dominance; nationwide presence
• Against Confusion: Limited geographic reach; modest sales; minimal advertising; recent entry to market; no evidence of actual consumer recognition

Factor 6: Number and Nature of Similar Marks in Use on Similar Goods

What's Analyzed: Whether there is a "crowded field" of similar marks, which may indicate that consumers are trained to distinguish between variations.

How to Prove:

• For weak mark (against confusion): Third-party registrations showing similar marks for similar goods; evidence of actual use in commerce of similar marks; industry publications showing widespread similar usage
• For strong mark (for confusion): Prove third-party marks are not actually in use; show that registered marks are meaningfully different; demonstrate your mark is unique in the field

Key Points:

• Evidence of third-party registrations alone may not be sufficient—actual use in commerce is what matters for Factor 6
• Recent Federal Circuit decisions clarified that when identical marks exist for identical goods, the burden shifts to the opposer to prove non-use
• Third-party evidence must involve marks that are similar, not just marks that share a common word
• The field must be "crowded" to dilute the strength of the prior mark—a handful of third-party uses typically isn't sufficient
• CRITICAL: The scope of "similar goods" under Factor 6 must be consistent with how similarity was defined under Factor 2

Common Arguments:

• For Confusion (stronger mark): Third-party marks are different in overall impression; registrations show non-use; applicant's mark directly targets senior user's mark
• Against Confusion (weaker mark): Widespread third-party use shows mark is weak/suggestive; consumers are accustomed to distinguishing variations; crowded field limits protection

Recent Development: The Federal Circuit's 2023 Spireon v. Flex decision established that when there are identical marks for identical goods in third-party registrations, the opposer must prove non-use. If non-use cannot be proven, the commercial strength of the opposer's mark will be considered weak.

Factor 7: Nature and Extent of Actual Confusion

What's Analyzed: Whether there is evidence of consumers actually being confused in the marketplace.

How to Prove:

• Survey evidence showing consumer confusion
• Customer complaints or inquiries
• Misdirected communications (emails, phone calls, mail)
• Testimony from consumers, employees, or industry participants
• Evidence from social media showing confusion
• Reports from sales or customer service staff

Key Points:

• CRITICAL: Actual confusion is "the best evidence" of likelihood of confusion and is "often considered highly probative" and "very persuasive evidence"
• Courts and the TTAB recognize that "such empirical data can be a reality check on the more theoretical analysis under the other factors"
• "The existence of actual confusion is normally very persuasive evidence of likelihood of confusion and undercuts any possible claim that the marks are so dissimilar that there can be no likelihood of confusion"
• Even a few well-documented instances can be significant and may outweigh dissimilarity in other factors
• Actual confusion is not required to find likelihood of confusion—but when present, it carries substantial weight
• However, absence of actual confusion is NOT dispositive: Courts repeatedly hold that "failure to prove instances of actual confusion is not dispositive against a trademark plaintiff, because actual confusion is hard to prove"
• Survey evidence must be properly conducted to be persuasive
• Inquiries about whether companies are related typically do NOT constitute actual confusion—they show consumers understood there were two different entities

Can Factor 7 Outweigh Factors 1 and 2?

Yes, it can be extremely powerful. While Factors 1 and 2 (similarity of marks and goods) are typically the most important, actual confusion evidence can:

• Provide a "reality check" that overrides theoretical analysis
• Demonstrate that despite any dissimilarities in marks or goods, consumers are in fact being confused
• Carry enough weight to establish likelihood of confusion even when marks or goods are not highly similar

However, courts analyze this holistically. Strong actual confusion evidence combined with even moderate similarity in marks/goods creates a powerful case. Conversely, the absence of actual confusion does NOT outweigh other factors pointing toward confusion—as the Federal Circuit emphasized in Sunkist v. KIST (2025), "actual confusion is inherently difficult to prove. Without more, lack of actual confusion is not dispositive as to whether confusion is likely."

Common Arguments:

• For Confusion: Consumer surveys showing confusion; documented incidents of actual confusion; misdirected communications; consumer testimony showing genuine confusion about source
• Against Confusion: No documented instances despite ample opportunity and substantial time period; different markets prevent consumer interaction; surveys showing no confusion; inquiries that demonstrate consumers knew companies were different

Factor 8: Length of Time During Concurrent Use Without Actual Confusion

What's Analyzed: How long the marks have coexisted without evidence of confusion, which may suggest confusion is unlikely.

How to Prove:

• Against confusion: Declarations from company executives stating length of concurrent use (with specificity about geography, timeframe); evidence showing overlap in markets; proof that no confusion complaints received; documentation of coexistence periods (decades of coexistence can be powerful)

Key Points:

• This is essentially the flip side of Factor 7
• Concurrent use without confusion can be powerful evidence against likelihood of confusion, particularly when marks have coexisted for many years in the same geographic area
• However, the absence of actual confusion may be explained by other factors (e.g., marks haven't actually been used simultaneously in same markets)
• Guild Mortgage established this factor must be addressed when record evidence supports it

Common Arguments:

• For Confusion: No meaningful coexistence; marks used in different markets; limited overlapping time period; no evidence party monitored for confusion
• Against Confusion: Decades of peaceful coexistence; same geographic market; similar goods; no confusion despite ample opportunity

Factor 9: Variety of Goods on Which Mark is Used

What's Analyzed: The breadth of goods/services on which the prior mark is used, suggesting either broader or narrower protection.

How to Prove:

• Catalog of all goods/services using the mark
• Evidence of mark's use across different product categories
• Registration portfolio showing scope of protection

Key Points:

• A mark used on a wide variety of goods may be entitled to broader protection
• Conversely, use on a narrow range may limit protection
• This factor is less commonly decisive than others

Factor 10: Market Interface Between Parties

What's Analyzed: Whether there are agreements, arrangements, or historical relationships between the parties that affect likelihood of confusion.

How to Prove:

• Against confusion:
  • Consent agreements with provisions designed to preclude confusion
  • License agreements showing coexistence arrangements
  • Settlement agreements with specified limitations
  • Evidence of laches or estoppel (senior user's delay in asserting rights)
  • Legitimate assignments of marks and goodwill

Key Points:

• A valid, enforceable consent agreement can eliminate likelihood of confusion concerns, though it must be genuine (not coerced) and must include actual limitations on use
• Laches and estoppel can be powerful equitable defenses
• Mere consent without restrictions may not be sufficient

Factor 11: Extent of Right to Exclude Others

What's Analyzed: Whether the applicant has any rights to exclude others, which may affect the scope of protection.

Key Points:

• This factor is rarely determinative in modern cases
• Relates to whether applicant has common law rights or prior registrations

Factor 12: Extent of Potential Confusion

What's Analyzed: Whether potential confusion is de minimis (minimal) or substantial.

Key Points:

• This is more of a conclusion than an independent factor
• Courts assess the overall magnitude and scope of likely confusion
• Even if some confusion exists, if it's de minimis, it may not be actionable

Factor 13: Any Other Established Fact Probative of Use

What's Analyzed: A catch-all for any other relevant evidence.

How to Prove:

• Prior coexistence agreements or court decisions
• Evidence of prior registrations for the same mark coexisting with cited mark
• Industry customs and practices
• Intent to confuse (bad faith adoption)
• Evidence of the applicant's other similar marks coexisting without issue

Key Points:

• Factor 13 provides flexibility for unique circumstances
• Under the Strategic Partners doctrine, if an applicant owns a prior registration for the same or nearly identical mark that has peacefully coexisted with the cited registration for at least five years, this can outweigh other factors pointing toward confusion
• This factor can be used for any "established fact" that illuminates the likelihood of confusion question

Two Critical Questions: Weight and Scope

Question 1: Isn't Actual Confusion Weighted Heavily? Can It Outweigh Similarity of Marks/Goods?

Yes—actual confusion (Factor 7) is considered "the best evidence" of likelihood of confusion and can be extremely powerful.

Courts and the TTAB repeatedly emphasize that:

• Actual confusion is "often considered the best evidence of likelihood of confusion" (King of the Mountain Sports v. Chrysler)
• "Such empirical data can be a reality check on the more theoretical analysis under the other factors" (Water Pik v. Med-Sys.)
• "The existence of actual confusion is normally very persuasive evidence of likelihood of confusion and undercuts any possible claim that the marks are so dissimilar that there can be no likelihood of confusion" (Brooklyn Brewery v. Brooklyn Brew Shop)

Can actual confusion outweigh dissimilarity in marks or goods?

Yes, it absolutely can. While Factors 1 and 2 (similarity of marks and goods) are typically the most heavily weighted, strong actual confusion evidence can:

1. Override theoretical analysis: When you have documented instances of real consumers being confused in the marketplace, this empirical evidence can outweigh abstract analysis of whether marks "look similar"
2. Demonstrate that confusion is actually occurring: This proves likelihood of confusion directly rather than inferring it from other factors
3. Carry enough weight to establish confusion even when marks or goods have some dissimilarities

Important caveat: The absence of actual confusion does NOT work the same way in reverse. The Federal Circuit emphasized in Sunkist Growers v. Intrastate Distributors (2025) that "actual confusion is inherently difficult to prove. Without more, lack of actual confusion is not dispositive as to whether confusion is likely."

In Sunkist, the TTAB found that four DuPont factors favored confusion (similarity of goods, trade channels, sales conditions, and strength of the SUNKIST mark), but dismissed the opposition because of lack of actual confusion. The Federal Circuit reversed, holding that "this single factor did not outweigh the other DuPont factors, all of which favored a finding that confusion between KIST and SUNKIST was likely."

Bottom line: Actual confusion is powerful evidence that can outweigh other factors. But absence of actual confusion doesn't have the same power to outweigh factors pointing toward confusion.

Question 2: Does the TTAB Look Beyond Identifications to Actual Products in the Market?

No—the TTAB analysis for Factors 2, 3, and 4 is strictly limited to the identification language in the application and registration. Actual marketplace conditions are irrelevant at the TTAB.

This is one of the most important—and often misunderstood—rules in trademark prosecution.

The Federal Circuit's holding in Stone Lion Capital Partners v. Lion Capital (2014) is controlling:

"The Court noted that the TTAB's determination was correct because its focus was on the trademark application and registered marks at issue rather than on 'real-world conditions.'"

"Parties that choose to recite services in their trademark application that exceed their actual services will be held to the broader scope of the application."

What this means in practice:

1. Factor 2 (Goods/Services): If your identification says "financial services," you will be judged against all financial services, even if you only provide mortgage banking

2. Factor 3 (Trade Channels): If your identification has no restrictions on trade channels, the TTAB will assume the goods/services could travel in all normal channels, regardless of how you actually distribute

3. Factor 4 (Sophistication): If your identification doesn't specify sophisticated purchasers, the TTAB will analyze based on the least sophisticated potential purchasers, even if you only serve Fortune 500 companies with $10 million minimum investments

The legal reasoning: As the Federal Circuit explained, the benefits of federal registration (nationwide constructive notice under 15 U.S.C. § 1072, presumption of validity, right to sue for infringement under § 1117) are "commensurate with the scope of the services recited in the application, not with the applicant's then-existing services."

Federal Court is Different: When you get to federal court in an actual infringement case, courts CAN and DO consider actual marketplace conditions, real customers, and how marks are actually used. This is why some cases that look bad on paper at the TTAB can have different outcomes in litigation.

Strategic Implications:

1. Carefully draft your identification to be as narrow as necessary to cover your actual and planned use
2. Add limitations where appropriate (e.g., "for sophisticated investors," "sold exclusively through medical professionals," "for industrial use")
3. Don't claim broader goods/services than you actually intend to use, even if you think it might give you broader protection
4. If facing a 2(d) refusal, you cannot argue "but we only sell to X type of customer"—the TTAB won't consider it unless it's in your identification

Common Strategic Approaches

For Trademark Applicants Facing Refusals:

1. Challenge Factor 1 (similarity):

   • Emphasize differences in overall commercial impression
   • Show marks create different meanings or connotations
   • Demonstrate visual, phonetic, or conceptual differences

2. Challenge Factor 2 (goods/services):

   • Argue goods are unrelated or complementary
   • Show different channels of trade
   • Provide evidence of distinct consumer bases
   • Narrow identification of goods/services to avoid overlap

3. Strengthen Factor 4 (sophistication):

   • Show high-priced products requiring careful purchasing
   • Prove specialized knowledge required
   • Demonstrate sophisticated business-to-business transactions

4. Leverage Factor 6 (crowded field):

   • Submit extensive third-party registration evidence
   • Prove actual use of similar marks in commerce
   • Show consumers are trained to distinguish between variations

5. Use Factor 8 (concurrent use):

   • Provide declarations showing peaceful coexistence
   • Document length of time without confusion
   • Demonstrate overlap in markets without issues

6. Invoke Factor 13 (other facts):

   • Point to prior coexistence of similar marks
   • Cite Strategic Partners doctrine if applicable
   • Show evidence of bad faith by opposer (if any)

For Mark Owners Opposing Registration or Proving Infringement:

1. Emphasize Factors 1 and 2:

   • Focus on similarity of marks and goods
   • Show overlap in dominant elements
   • Prove goods are related, complementary, or travel in same channels

2. Establish Factor 5 (fame):

   • Provide sales, advertising, and market share data
   • Submit consumer surveys showing recognition
   • Document media coverage and industry recognition

3. Prove Factor 7 (actual confusion):

   • Conduct consumer surveys
   • Document confusion incidents
   • Gather testimony from affected consumers or employees

4. Downplay Factor 6:

   • Prove third-party marks are not in actual use
   • Distinguish third-party marks as meaningfully different
   • Show your mark is distinctive and strong in the field

Key Differences: TTAB vs. Federal Court

While both the TTAB and federal courts use the DuPont factors, there are important procedural and evidentiary differences:

At the TTAB:

• Analysis is based on the identification of goods/services in the application and registration, not actual marketplace use
• Less emphasis on actual confusion evidence (Factor 7) because:
  • TTAB cases often involve applicants who haven't begun using their marks yet
  • The "projection test" asks whether confusion would be likely if both marks were used on the full scope of identified goods
• Heavier reliance on third-party registrations and prosecution history
• Limited discovery compared to federal court

In Federal Court:

• Analysis can consider actual marketplace conditions
• Strong emphasis on actual confusion evidence (surveys, testimony, incidents)
• More extensive discovery allows for detailed market evidence
• Expert testimony is common (survey experts, industry experts, damages experts)
• Courts may consider evidence of defendant's intent (bad faith adoption)
• Preliminary injunction standards require showing likelihood of success on the merits

Avoiding Mechanical Tallying

The Federal Circuit has repeatedly warned against "mechanically tallying" the DuPont factors. In Citigroup v. Capital City Bank, the Court emphasized that simply counting up which factors favor each side is improper because the factors have differing weights.

Instead, courts and the TTAB must:

• Consider the totality of the circumstances
• Weigh factors based on their relative importance in each specific case
• Recognize that one strong factor (like near-identical marks on identical goods) can outweigh multiple neutral or slightly favorable factors
• Analyze factors in an interconnected manner—conclusions about one factor may affect analysis of others

Recent Federal Circuit Guidance

Consistency is Critical

The 2025 case Apex Bank v. CC Serve Corp. reminded the TTAB that consistency across factors is non-negotiable. If the TTAB finds services are "highly similar" or "legally identical" under Factor 2, it must apply that same standard of similarity when evaluating Factor 6 (third-party use on "similar goods").

The Federal Circuit held that "when the Board has already made a factual finding that the services are highly similar—in fact, partially legally identical—in its analysis of the second DuPont factor, the Board should retain the same scope in its consideration of similarity under the other factors."

Interconnected Analysis

The DuPont factors don't exist in isolation. Changes to the analysis of one factor can have cascading effects on others. For example:

• Reconsideration of Factor 6 (third-party use showing weak commercial strength) affects Factor 1 (overall commercial impression of the marks)
• Factor 5 (fame) influences Factor 1 (commercial impression) and Factor 2 (breadth of protection for goods)
• Factors 7 and 8 interact—actual confusion weighs toward likelihood of confusion, while concurrent use without confusion weighs against it

The TTAB Must Explain Its Reasoning

While the TTAB has discretion in weighing factors, it must provide ascertainable reasoning showing how it weighed the factors and reached its conclusion. The Federal Circuit has remanded cases where the Board's reasoning was unclear or where the Board failed to explain why one set of factors outweighed another.

Practical Takeaways

1. The first two factors matter most: If you can establish strong similarity in either marks or goods, you're halfway to proving likelihood of confusion. Conversely, strong dissimilarity in both factors makes proving confusion difficult.

2. Document everything: Evidence is king. For concurrent use arguments, get declarations. For fame, compile sales and advertising data. For third-party use, document actual use in commerce.

3. Consider all relevant factors: Don't ignore factors that cut against you. Address them head-on and explain why other factors should be given more weight.

4. The application matters: Broad identifications of goods/services create broader potential for conflict. Consider narrowing descriptions strategically.

5. Surveys can be powerful: Well-designed consumer confusion surveys carry significant weight in both TTAB proceedings and federal court.

6. Timing matters for concurrent use: Decades of peaceful coexistence is powerful evidence against confusion, but it must be properly documented and argued.

7. Third-party use requires proof: Don't just submit registrations—prove marks are actually being used in commerce. Under Spireon, if you're the opposer and there are identical marks for identical goods, be prepared to prove non-use.

8. Consent agreements must be meaningful: A simple consent letter may not be enough. Include substantive provisions limiting use to show that confusion is being managed.

9. Fame is a spectrum: Don't assume you need to be Coca-Cola level famous. Even moderate marketplace recognition can strengthen your position.

10. Watch for inconsistency: If the TTAB or a court applies different standards across factors, that's a potential basis for appeal.

Conclusion

The DuPont factors provide a comprehensive and flexible framework for analyzing likelihood of confusion—the cornerstone of trademark law. While the factors may seem complex, understanding how they work in practice is essential for effective trademark strategy.

The key principles to remember:

• All relevant factors must be considered when there's record evidence
• Factors 1 and 2 typically carry the most weight, though any factor can be determinative depending on the circumstances
• Mechanical tallying is prohibited—analysis must consider the totality of circumstances and the relative weight of factors
• Consistency across factors is critical—definitions of "similarity" must be applied consistently
• Evidence is essential—strong factual support for your position on each factor improves your chances significantly

Whether you're selecting a trademark, responding to an office action, opposing another's registration, or preparing for litigation, a thorough understanding of the DuPont factors—and how to prove or rebut each one—will serve you well.

The Federal Circuit's recent decisions make clear that courts are holding the TTAB to high standards of rigorous, consistent analysis. As trademark law continues to evolve, these thirteen factors remain the bedrock of likelihood of confusion analysis, guiding decisions that affect billions of dollars in brand value and shape the competitive landscape across industries.

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This article is for informational purposes only and does not constitute legal advice. Trademark matters are highly fact-specific, and the outcome of any particular case depends on its unique circumstances. Consult with a qualified trademark attorney for advice on your specific situation.

FAQ

What are the DuPont factors in trademark law?

Thirteen factors guide whether marks are confusingly similar. Strength, relatedness, and channels carry the most weight.

How do I rebut a likelihood-of-confusion refusal?

Provide evidence on marketplace separation, distinct channels, consumer sophistication, and narrow IDs when helpful.

Which DuPont factors matter most at the USPTO?

Similarity of marks, relatedness of goods/services, and evidence of actual confusion dominate outcomes.

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