연기금의 운용목표는 장기적인 안정적 수익추구와 잠재위험 최소화를 통한 기금의 후생증대이다. 따라서, 영구펀드의 운용목표에 적합하고, 장기적인 듀레이션을 갖는 자산을 편입하는 것은 장기투자자산 운용자의 중요한 임무 중 하나이다. 최근 국민연금을 포함한 국내외 연기금들은 장기투자자산의 선별요소로 환경(Environment), 사회(Social), 지배구조(Governance) 등 비재무적 요인의 포트폴리오 반영을 적극적으로 고려하고 있다. 본 연구는 ESG투자라고 알려져 있는 자산들을 장기투자자의 전략적 자산배분에 포함시킬 때 포트폴리오의 최적 자산이 사회적 후생에 어떤 영향을 주는지에 대하여 일반균형모델을 이용하여 검토하였다. 전통적인 포트폴리오선택이론에 기반한 자산배분론인 평균-분산이론에 따르면 장기투자자인 연기금의 책임투자자산 편입에 대한 평가는 다양한 견해가 존재한다. 장기투자자측면에서 사회적 효용함수를 이용한 일반균형이론(general equilibrium theory)을 활용한 자산배분방법은 평균-분산 방법론과 대비하여 우월한 분석법이 될 수 있다고 판단된다. 사회적 책임을 적극적으로 수행하는 기업이 기업의 가치도 높일 수 있다는 측면에서 ESG자산의 성과는 장기적으로 우수한 것으로 평가되고(김창수(2011, 2019)), 사회적 후생의 개선에도 기여할 수 있다는 측면에서 ESG자산이 연기금포트폴리오자산으로서 중요한 역할이 가능할 것으로 보인다. 모형변수는 국내주식, 국내ESG주식, 국내채권 등 3가지 자산으로 선정하였고, 주식자산과 ESG자산은 GBM모델, 채권은 Vasicek 모형을 갖는 것으로 가정하였다. 장기투자자의 효용함수는 멱효용함수(power utility function)를 사용하였고, Brennan et al(2002)의 가정에 따라 지수형 아파인(Affine)형태의 간접효용함수를 사용하였다. 간접효용함수의 편미분값을 활용하여 최적포트폴리오비중을 도출하였고, 최적자산배분의 회귀분석을 통해 영향을 미치는 요인을 검토하였다.
Domestic and foreign pension funds, such as the National Pension Service, are permanent funds that seek to manage assets with long-term durations. This is because one of the most significant roles of long-term asset managers is adding assets that increase the funds’ welfare by minimizing the potential risk of investment assets and gaining a stable, long-term rate of return. As the problems of shareholder capitalism widen, the market participants are all becoming increasingly aware of sustainable growth and stakeholder capitalism with ESG investments is alternative. After the enactment of Korean-stewardship code in 2016, the last 5 years have seen incresing recognition of the importance of ESG assets and many long-term investors invest ESG related assets more and more. The additional effect of the inclusion of ESG investment, which takes non-financial aspects such as environment, social, and governance into account, in optimized strategic asset allocation on the portfolio’s welfare improvement, was examined using general equilibrium model. we develop a simple framework without inflation and foreign exchange rate for analyzing a finite-horizon investor’s asset allocation problem. The investor’s optimal investment strategy and indirect utility are given in simple closed form. The simple partial equilibrium analysis in this paper shows that the avalibility of ESG equity instruments can have a very significant effect in improving investor welfare. While the traditional mean-variance portfolio theory is accepted as an asset allocation idea based on financial values, despite the substantial amount of research, various views surround the asset allocation effect of responsible investment in the short term. From the perspective of long-term investors such as pension funds, an asset allocation method that employs a social utility function-based general equilibrium model may be a meaningful analysis method. The investor’s optimal portfolio is shown to be a sum of two components: first, the mean-variance tangency portfolio and second, a portfolio that mimics as closely as possible a hypothetical indexed bond with maturity equal to the investment horizon. It can derive sophisticated optimal investment allocations. As the companies followed CSR(Corporate Social Responsible) have high value, ESG Asset is superior in the long run(Kim (2011,2019)) and can play a central role in pension funds’ portfolio. Three types of assets, domestic stocks, domestic ESG stocks, and domestic bonds, were selected as model variables, under the assumption that domestic stocks follow the GBM(Geomtrric Brownian Motion) model and that bonds follow the Vasicek model. As for the utility function of the long-term investors, the power utility function was used, while an indirect utility function following the Exponential-Affine model was derived based on assumptions in Brennan et al (2002). The optimal portfolio was derived using the partial derivative values of the indirect utility function, and this thesis reviewed the multi-regression analysis of optimal asset weight. Though there are various ways to classify ESG asset investment methods, the absence of each relevent benchmark indexes is a big problem applying to use asset allocation models. This is because it is difficult to evaluate portfolio excess performance. the reviews about foreign ESG markets and various ESG benchmark studies in advanced countries will make more systematic asset allocation approaches. As general equilibrium setting is extensible to anlayze various models, further researches for improvement of social welfare can be developed.