本文主要讲的是MPT的关键要素，基于MPT，已经确定了个股收益的两类风险。经济衰退、利率冲击、战争等市场风险的系统性风险不易分散(Pfiffelmann, Roger and Bourachnikova, 2016)。非系统风险是具体的风险，因为它是具体的个股。通过增加投资组合中的股票数量，可以很容易地分散个股的非系统风险。Markowitz(1952)提出的MPT的关键要素如下。本篇ps代写文章由美国论文人EducationRen教育网整理，供大家参考阅读。
Based on the MPT, two types of risks for individual stock returns have been identified. The systematic risks which are the market risk such as recessions, interest rate shocks and wars are not easily diversified (Pfiffelmann, Roger and Bourachnikova, 2016). The unsystematic risks are the specific risk as it is specific to individual stocks. The unsystematic risk for individual stocks can be easily diversified by increasing the number of stocks in the portfolio. The key elements of the MPT proposed by Markowitz (1952) are explained below.
Investors or the portfolio managers engage in the decision-making process based on the expected returns and the variance of the returns. The historical mean of the returns from an asset over a given time period derives the expected return from an asset. It must be noted that the terms mean and expected returns are interchangeable (Pok and Poshakwale, 2004).
The theory justifies that the portfolio selection is not based on the risk associated with the individual securities. The risk involved in the portfolio selection is based on the portfolio risk. The theory encompasses the combination of risky assets and expected returns from a portfolio which reflects relatively low risk. Conversely, it can be stated that it is quite possible to develop a portfolio with lower risk as compared to the sum of its counterparts.
The portfolio managers are alarmingly learning the key components of the MPT in order to manage risk and maximize its return. The main of this theory is that it ensures that the portfolio managers are able to derive the greatest potential return coupled with least risk. A portfolio manager through this theory is able to measure the relationship between the numerous types of investments (Shipway, 2009). In this way, the portfolio managers are able to compare and contrast between the risks and returns of the portfolio assets and investments which would help them to reduce risk and sustain maximum returns. MPT is regarded as a financial self-defense for the portfolio managers in which diversification is the way to smooth out the rough edges of the returns on investment. The basic idea of the MPT is based on the efficient portfolio which represents the investment opportunity set based on expected portfolio return and portfolio risk.