Supreme Court Decision 2017Da292343 Decided May 26, 2022 【Wages, etc.】

【Main Issues and Holdings】
[1] Whether Article 4-4(1) of the former Act on Prohibition of Age Discrimination in Employment and Elderly Employment Promotion that prohibits discrimination on the basis of age is an imperative provision (affirmative)
[2] Meaning of “without justifiable grounds” in Article 4-4(1) of the former Act on Prohibition of Age Discrimination in Employment and Elderly Employment Promotion
Standards for determining whether the system under which workers are allowed to work until the retirement age is attained, but at a reduced wage, for a given period until the workers are of retirement age, i.e., a so-called “peak wage system,” is invalid as there are no justifiable grounds for discrimination on the basis of age
[3] In the case where: (a) Research Institute A adopted a performance-based wage system, under which the existing retirement age was maintained at the current level of 61, while the wage was reduced for regular employees above age 55, after agreement with its trade union on new HR and wage system; and (b) Party B, an employee of Research Institute A, sought payment of reduced wages by arguing that the performance-based wage system adopted by the research institute was in violation of the former Act on Prohibition of Age Discrimination in Employment and Elderly Employment Promotion and was thus invalid, the case holding that the performance-based wage system in the instant case constituted discrimination against Party B on the basis of age in terms of wages and that there are no justifiable grounds for discrimination