Aquilian liability, a fundamental aspect of South African law, serves as a pivotal mechanism for redressing unlawful competition. This legal framework empowers those who suffer financial losses due to wrongful competition or unethical trading practices. This article comprehensively examines Aquilian liability within the context of unlawful competition, delving into its historical origins, diverse manifestations, considerations of fault, protected interests, the concept of wrongfulness, and available remedies.

Historical Evolution 

The roots of Aquilian liability for unlawful competition in South African law extend back to the influential case of Matthews v Young. This landmark case marked the inception of the concept, emphasizing the necessity of maintaining lawful boundaries in the realm of competition. While individuals possess the freedom to engage in trade and professions, they must do so without unjustly encroaching upon others. Instances of unlawful interference leading to direct financial losses can instigate legal action under the lex Aquilia.

Expansive Scope of Aquilian Action 

South African law recognizes an expansive and adaptable action for unlawful competition, firmly anchored in the principles of the lex Aquilia. Courts have consistently applied these principles to address various forms of unlawful competition, encompassing passing off, misrepresentation, trade secret misappropriation, copying a competitor’s work, competition that contravenes statutory provisions, and boycotting.

Flexibility in Legal Protections 

One noteworthy implication of acknowledging Aquilian liability within the context of unlawful competition is its inherent flexibility. Courts are empowered to develop new forms of protection against unlawful competition, even in the absence of direct legal precedent. This adaptability enables responsive solutions to emerging challenges in the competitive landscape.

Classification of Unlawful Competition 

While Aquilian principles are broadly applicable, courts often categorise cases of unreasonable competitive or trading conduct into established forms of unlawful competition. This classification streamlines legal proceedings while allowing for the evolution of detailed sub-rules within each category.

Prominent Forms of Unlawful Competition 

Several common forms of unlawful competition frequently emerge, including:

  • Passing Off: Misrepresenting one’s business or product as identical or associated with another’s.
  • Misappropriation of Trade Secrets: The unauthorised use or disclosure of confidential information possessing commercial value.
  • Copying and Exploiting Competitor’s Work: Appropriating a rival’s creative output.
  • Improper Use of a Trade Name: The utilisation of another’s trade name or personal image for advertising purposes.
  • Misappropriation of Intellectual Property: Unauthorized use of copyrighted or trademarked materials.

Fault in Unlawful Competition 

Unlawful competition typically involves intentional conduct, though distinguishing between competitive practices and deceptive actions can be challenging. South African law also acknowledges negligence as a factor in unlawful competition cases.

Interests Protected by Aquilian Action 

The paramount interest protected by the Aquilian action for unlawful competition is the right to goodwill. This encompasses various facets, including reputation, product names, trademarks, and trade secrets. The crucial requirement is the establishment of actual or potential harm to trade or the capacity to attract customers.

Determining Wrongfulness 

Evaluating wrongfulness in unlawful competition necessitates consideration of fairness, honesty, societal interests, market ethics, and prevailing business norms. Public policy considerations play a central role in making this determination.

Remedies and Damages 

South African courts award damages to compensate for harm inflicted by unlawful competition, adhering to standard principles applicable to financial harm. While quantifying harm with precision can be challenging, courts rely on evidence probabilities for their assessments. In many instances, interdicts or injunctions prove to be the most effective remedy, compelling wrongdoers to cease unlawful competition or unethical trading practices.


Aquilian liability for unlawful competition remains a robust legal framework in South African jurisprudence, effectively addressing various forms of competition-related harm. Rooted in historical precedents, this legal doctrine continually adapts to new challenges, upholding the rights of individuals and entities against unfair practices in the competitive marketplace. Contact an expert at SchoemanLaw for you legal needs.