Given the use of abstract and comprehensive concepts, one may question whether “an act that causes considerable harm to the interests of consumers” prescribed in the latter part of the Article 3-2 (1) 5 of the Monopoly Regulation and Fair Trade Act per se is not against the rule of clarity. However, in light of the limitations of legislative schemes and the existence of concrete signs suggesting that the requirements for such act, i.e., remarkable nature and unfairness, have been met, the Supreme Court’s view that the wording does not contradict the rule of clarity is reasonable. However, to enhance predictability for the offender, there is need to more concretely define the types of and standards for such act. Since it is reasonable to view the above provision to contain separate requirements supplementing Subparagraphs 1 and 2 of the same Paragraph, prohibiting extortion and abuse in regard to consumers, the interests of consumers here should exclude the physical and safety interests of consumers that are under indirect protection of the Monopoly Regulation and Fair Trade Act while including non-economic benefits such as consumers’ right of free choice and incidental conveniences. As for the standards to determine the remarkable nature, it was reasonable for the Supreme Court to employ objective comparison methods such as comparison with trade conditions in comparable markets (comparing trade conditions altered by the relevant act with trade conditions of other business operators in comparable markets) and price/cost analysis (comparing price increases attributable to the relevant act with the degree of change in the cost of business operators with market dominance). However, this is merely an example and need not be clung to. Therefore, an individual approach is needed for determination. An act that causes considerable harm to the interests of consumers tends to be an act whose purpose is to enjoy dominance rather than to maintain or strengthen dominance, and thus, the Supreme Court was reasonable in applying different standards to determine unfairness of such act from those applied to exclusionary abuse. Also, since there are a wide variety of types of act and the intent and purpose of the persons committing such act would not be uniform, it is reasonable to demand subjective intent or purpose.