In this study, we propose a welfare loss model to analyze the effect of market structure on the welfare of each market in the telecommunication market. Using the objective data published by the actual broadcasting communication market, we estimated the social welfare loss amount for the next five years from 2017 to 2021. As a result, the consumer surplus in the mobile communication market is about 23~24 trillion won, which is about 7% (3.1~3.4 trillion won) in annual social welfare loss. Consumer surplus of broadband internet is about 3~5 trillion won, and social welfare loss is about 10% (3-4 billion). Consumer surplus in the pay-TV market is about 20 trillion won, which is the lowest level of social welfare loss at 1% (3~400 billion won). Consumer surplus in the combined market is about 10~15 trillion won, and social welfare loss is about 1~2 trillion won. Assuming that the monopolistic market share of each market is eased, the social welfare loss in the mobile communication market is about 2.5~2.7 trillion won, which can save about 5~800 billion won in losses. In the high-speed internet market, the welfare loss level is about 500~800 billion won, which can save about 2~400 billion won loss. In the pay-TV market, the loss of social welfare is about 2~300 billion won, which can save about 800~100 billion won loss. In the combined market, the welfare loss amount is about 600 billion won  ~ 1 trillion won, which means that the average loss of 1 trillion won can be saved. In other words, in order to develop related industries through promoting user welfare and creating a competitive environment in the broadcasting and telecommunication market, it is suggested that dominance relaxation is a priority in accordance with the basic principles of fair competition regulation.

mobile communication market, broadband internet market, paid broadcast market, combined market, consumer welfare, welfare loss, fair competition.