본 연구는 이동통신사의 통신원가를 대상으로 법인세 배부에 대한 사례를 분석하였다. 현행 전기통신사업법 회계분리기준에 따른 총괄원가에 포함되는 법인세비용은 실무적으로 재무회계상 법인세비용을 그대로 인식하고 있어 특정연도의 이동통신사업자의 유효법인세율이 크게 나타나거나 음(-)의 법인세비용이 발생하는 경우 원가왜곡이 발생한다. 따라서 본 연구의 목적은 규제서비스관점에서의 총괄원가를 합리적인 수준으로 산정하고, 총괄원가를 산정함에 있어 기획재정부의 2013년 공공요금 산정기준에 따라 법인세비용을 재산출함으로써 개별 공공요금간의 일관성과 정합성을 제고하자 한다. 분석 결과 기획재정부의 공공요금 산정기준에 따라 산출된 법인세비용을 사용할 경우 특정연도에 총괄원가가 과대 또는 과소 계상되지 않는 것으로 나타났다. 이는 기획재정부의 공공요금 산정기준에 따라 산출된 법인세 비용은 통신요금 정책결정을 위한 기초자료로서 목적적합하게 사용될 수 있을 것으로 기대한다. 또한, 현행 전기통신사업 회계분리기준 제30조는 법인세비용을 영업손익비율 기준에 따라 서비스별로 배부하고 있다. 현행기준에 따르면 음(-)의 법인세비용이 발생하는 경우 영업이익이 발생하는 서비스에 음(-)의 법인세가 배부되고, 영업손실이 발생하는 서비스에 양(+)의 법인세가 배부되어 서비스별 원가왜곡이 발생할 수 있다. 따라서 본 연구에서는 서비스별 영업손익에 법정세율을 곱하여 산정하고, 세무상 조정사항을 역무별 공통비용으로 정의하고, 투자보수의 기준이 되는 요금기저를 기준으로 서비스별로 배부하였다. 분석 결과, 서비스별 편차가 있으나 영업이익이 크게 발생한 서비스의 경우 본 연구에서 제시한 서비스별 투자보수기준 법인세비용과 현행 법인세비용이 큰 차이를 보이는 것으로 나타났다. 즉, 요금인하여력 등 요금수준을 확인하기 위한 참고자료로서 원가보상율을 활용하는 경우 법인세비용 배부에 따른 차이는 통신서비스 요금산정에 큰 영향을 미칠 수 있으므로 합리적인 법인세비용의 배부방안에 대한 논의가 적극 검토되어야 한다는 것을 시사한다.

In the early 2000s, the government induced firm to enter the mobile telecommunication industry which demands a massive investment as it is one of national information infrastructures. Despite of higher initial investment, mobile telecommunication industry brought the first movers to make a huge profit because the industry is monopolistic and oligopolistic and customer’s demand is consistently increased. These facts can be proved to the number of mobile phone service subscriber, about ten million people in 2015. As complaints about mobile service has increased, the public interest is growing in not only mobile telecommunication price but also mobile telecommunication costs. They raise a question whether pricing mobile communication service is reasonable. Once again, these public interest also boost academic interest, such as calculation method and components of telecommunication cost. This case study focuses on the allocation of corporate tax expense with mobile telecommunication cost in telecommunication firms among various academic issues. The followings are the reason of choosing this specific issue. First, according to the current accounting separation standards in the Telecommunication Business Act, the corporate tax expense included in aggregate cost is practically considered the same as the corporate tax expense of Financial Accounting Standards. Estimating corporate tax expense is critical point in not only aggregate cost but also cost recovery rate. Moreover, the aggregate cost is one of the relevant information for establishing and carrying out mobile telecommunication policy. Corporation tax expense is also one of the main components of the aggregate cost, and the impact of corporation tax expense on aggregate cost is to a considerable extent as the level of corporation varies depending on the recognition basis of corporation tax expense or service allocation basis. Under the current system, cost could be distorted in the case of that effective tax rate is large enough in the particular year, or corporate tax expense appears to be negative value. Therefore, the purpose of this study is calculating the reasonable aggregate cost to improve consistency and coordination among public utility charges. Computing aggregate cost is also able to recalculate the corporate tax expense on the basis of scoring criteria of public utility charges published by Ministry of Strategy and Finance in 2013. Aggregate cost including corporate tax expense is expected to be reasonable basic data for a policy decision of telecommunication fee if corporate tax expense is calculated by scoring criteria of public utility charges published by Ministry of Strategy and Finance. Under the current system, the aggregate cost is generally overestimated or underestimated due to the irregularly occurred corporate tax expense. Moreover, corporate tax expense is currently distributed across the service on the basis of operating income ratio under the accounting separation standards. In this case, the cost also could be distorted because the service which makes a profit pays negative value of corporate tax expense, otherwise, the services which makes a loss pays positive value of corporate tax expense. Therefore, this study suggested the cost allocation across the service by below procedures. To improve current allocation method, we multiply operating profit and loss across the service by tax rate, and then we define common expense as deduct profits which are not taxation objects, adjustment details in the concept of financial accounting. Lastly, we set the cost as the basis of compensation on operating assets. Analysis results shows that there is a big gap between the corporate tax expense calculated by current system and calculated by our suggestion in the case of profitable service. That is, cost difference by allocating corporate tax expense has a great effect on the policy decision of telecommunication fee such as demanding reduction of fee, compensation of cost. Therefore, this paper suggests that government gives positive consideration to rational allocation plan and policy for corporate tax expense when deciding telecommunication fee. This paper also has limit to discuss the allocation of not overall factors but corporate tax expense when estimating aggregate cost. Further research should consider the effect of corporate tax expense on telecommunication accounting by examining the relation between corporate tax expense and compensation rate on operating asset before or after tax.