An Explanation of Trademark Infringement and Likelihood of Confusion

Trademark infringement is a troublesome and unfortunate aspect of the business environment, but it happens regularly. Entrepreneurs and business owners should have a good understanding of what trademark infringement is and how it works. Generally, trademark infringement occurs when a party uses a mark that is identical or confusingly similar to a mark owned by another without the permission of the trademark owner. This article explains trademark infringement, and how infringement is evaluated through the likelihood of confusion factors laid out in In re E.I. du Pont de Nemours & Co., 476 F.2d 1357 (C.C.P.A. 1973).

Understanding Trademark Infringement

A trademark or service mark is a symbol, word, or phrase used to identify and distinguish goods or services of one party from those of others. When a trademark owner believes that another party's use of a particular mark is likely to cause confusion among consumers regarding the source of the goods or services, they may file a trademark infringement claim. The key to such claims is proving the likelihood of confusion between the two marks.

Likelihood of Confusion

The likelihood of confusion analysis is a standard used by courts to determine whether trademark infringement has occurred. It assesses whether consumers are likely to believe that the goods or services offered under the allegedly infringing mark come from the same source as those offered by the trademark owner under their mark. Various factors, known as the DuPont factors, are considered in this analysis, including:

1. Similarity of the Marks

The most critical factor is the similarity between the defendant's mark and the plaintiff's mark in appearance, sound, meaning, and overall commercial impression. The more similar the marks, the more likely consumers will be confused.

2. Similarity of the Goods or Services

The relatedness of the goods and services associated with the marks is also important. Similarity increases the likelihood of confusion. A similar mark used on related goods and/or services are more likely to confuse consumers than if the goods and or services are unrelated. To illustrate, the mark Delta can be used on both airline services by one company and faucets by another without confusing consumers.

3. Channels of Trade

The marketing channels through which the goods or services are sold are also considered. If both marks operate in similar channels, the likelihood of confusion is higher. Channels of trade refer to the various methods and pathways through which a good or service is marketed and sold to consumers. These include retail stores, online platforms, wholesalers, and other distribution networks. Similar channels of trade between two products can increase the likelihood of consumer confusion regarding their source.

4. Conditions of Sale

The conditions under which sales are made, such as the degree of care exercised by consumers, affect the likelihood of confusion. Expensive or sophisticated products may involve more careful purchasing decisions, reducing the likelihood of confusion. Small, inexpensive purchases that require little thought weigh in favor of finding confusion.

5. Actual Confusion

Evidence of actual consumer confusion between the two marks in the marketplace is strong evidence of likelihood of confusion. Actual confusion occurs when the similarity between marks creates a mistaken belief that a good or service from different companies come from the same source. For example, if shoppers buy "Sunny Day" juice thinking it is "Sunny Delight" juice, it illustrates actual confusion caused by the similarity of the marks.

6. Defendant's Intent

If the defendant intended to create confusion or benefit from the trademark owner's mark's reputation, it supports a finding of likelihood of confusion. Bad faith weighs in favor of a finding of likelihood of confusion because the court will allow the defendant's bad act to weight against them.

7. Strength of the Mark

The distinctiveness and recognition of the trademark owner's mark in the market can influence the likelihood of confusion. Stronger marks are afforded broader protection.

Key Factors in Determining Likelihood of Confusion

Not all factors carry the same weight in every case. The importance of each factor varies depending on the particular circumstances of the case. For example, in some cases, the similarity of the marks might be the most crucial factor, while in others, the strength of the mark or evidence of actual confusion might be more significant.

Consumer Confusion and Commercial Relationships

The likelihood of confusion analysis aims to protect the market from being misled about the source of goods or services. A key consideration is whether the allegedly infringing mark creates a similar commercial impression as the trademark owner's mark, potentially confusing consumers into believing the goods or services come from the same source.

Enforcement of a Registered Mark vs. Unregistered Mark

A registered trademark or service mark offers several advantages over an unregistered mark when enforcing trademark rights in federal court. Firstly, a registered mark provides a legal presumption of ownership and exclusive rights to use the mark nationwide for the goods or services listed in the registration. This simplifies the burden of proof in court, as the trademark owner does not need to establish prior use. Additionally, registering a mark on the Principal Register grants the trademark owner the ability to bring an infringement suit in federal court and potentially recover statutory damages and attorney's fees. A registered mark also benefits from public notice of ownership, which can deter potential infringers. Moreover, a US registration can serve as a basis for registering a mark in foreign countries and can help in preventing the importation of infringing goods. These advantages collectively strengthen the trademark owner's position in enforcing their rights and protecting their brand.

Trademark Protection and Registration

Trademark registration provides several advantages, including the legal presumption of ownership and exclusive rights to use the trademark nationwide for the goods and services listed in the registration. However, even without registration, a trademark owner can pursue an infringement claim based on common law rights established through use of the mark in commerce.

The Role of the USPTO

The United States Patent and Trademark Office (USPTO) is the federal agency that handles the trademark process. When an applicant files a trademark application, an assigned USPTO examining attorney reviews it to analyze whether the mark is eligible for registration on the principal register. One of the primary reasons for refusing registration is the likelihood of confusion with an existing registered mark.

Office Actions and Refusals

A trademark application must be submitted to the USPTO in order to register a trademark.  The trademark application is reviewed by a trademark examiner to evaluate whether the mark meets the requirements of registration.  The trademark examiner conducts a search of prior-filed trademark applications and registered mark to determine whether conflict exists with a prior mark. If the examining attorney determines that a likelihood of confusion exists between the applicant's mark and a registered similar trademark, they issue an office action refusing the trademark application based on confusion refusal. The examining attorney employs the same likelihood of confusion analysis that is used to determine trademark infringement. If the mark claimed in the pending application is too similar to a registered mark, the examining attorney will likely refuse registration. The applicant or their trademark attorney may respond to this refusal by presenting arguments and evidence to overcome the likelihood of confusion determination.

The Appeal Process

If the USPTO denies a trademark application due to likelihood of confusion, the applicant can appeal the decision to the Trademark Trial and Appeal Board (TTAB). The TTAB reviews the examining attorney's decision and considers the applicant's arguments and evidence.

Court Proceedings and Determinations

When a trademark or service mark is infringed, an infringement claim may filed in federal court. Trademark infringement claims can alternatively be filed in state courts. The court examines the likelihood of confusion between the conflicting marks considering the same principal factors used by the USPTO, but will also consider real world, practical information, such as market surveys, expert testimony, and incidents of actual confusion that are not part of the analysis in the trademark examination process.

Case Examples

To illustrate the application of these principles, consider the following examples:

  1. Restaurant Services: If a restaurant named "Bistro Bella" sues another restaurant called "Bistro Bella Italia" for trademark infringement, the court will analyze the similarity of the marks, the relatedness of the restaurant services, and any evidence of actual confusion among customers.

  2. Similar Trademarks in Related Goods: In a case involving similar trademarks for clothing brands, the court would examine the marks' similarity, the overlapping target consumer base, and the marketing channels used by both parties.

The Role of Trademark Attorneys

Trademark attorneys play a vital role in navigating trademark law and protecting trademark rights. A trademark attorney assists clients in conducting trademark searches, filing trademark applications, responding to office actions, and litigating trademark infringement claims. Their expertise is crucial in assessing the likelihood of confusion and developing strategies to protect their clients' marks.


Trademark infringement and the likelihood of confusion are central issues in trademark law. The analysis involves a detailed examination of various factors to determine whether there is a likelihood of confusion with similar marks. The USPTO and federal courts use these principles to assess whether a trademark application claims a valid mark and whether an infringement claim has merit, ensuring that trademark owners' rights are protected when warranted and preventing consumer confusion. Understanding the nuances of this analysis is essential for trademark owners, applicants, and attorneys to navigate the complexities of trademark protection and enforcement.

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