수탁자의 투자의무 - 신중한 투자자 원칙을 중심으로-

The Prudent Investor Rule has been a familiar feature in Anglo-American law of trust. In the formulation of Restatement of (Third) Trust and Uniform Prudent Investor Act, the trustee has a duty to diversify the investment and incorporate the return-risk investment strategy. Historically, England developed a restricted list of proper trust investments, initially government bonds and first mortgage and expanded to include other investments. Only in 1961, Trustee Investment Act allowed trustees to invest in equities. Later, Trustee Act 2000 adopted the more liberal approach, for which the Prudent Investor Rule in USA was influential. Although, some states in USA adopted so called legal lists from UK, Harvard College v Amory case in Massachusetts developed the Prudent Man Rule and it became the important authority. The Prudent Man Rule was more advanced than legal lists rule because it abandoned the restricted investment approach. However, it still forbade risky investments and preferred safe investments such as long-term government bonds. Also, it was applied to investment individually, not in the context of trust whole portfolio. During the inflation period, however, the bonds became susceptible to inflation risk. Thus, it was not deemed safe anymore. Furthermore, finance theory made rapid progress from 1950 onwards and academics and practitioners thought it was necessary to repudiate the prior legal lists rule and prudent man rule. Hence the Prudent Investor Rule was created. This paper examined the development of Prudent Investor Rule in USA, which puts more emphasis on risk management than risk avoidance. Under the rule, the trustee should implement the overall investment strategy considering the risk and return objectives suited to the trust. Also, the Prudent Investor Rule reorients trust investment from risk avoidance to risk management in keeping with portfolio theory and CAPM theory. In Korean Trust Act, the legislatively approved investment lists (§41) were codified in 2011 and have not yet been amended. In the same vein, §105 Financial Investment Services and Capital Markets Act adopted the legal list rule approach for professional trust business entities. This article argues that the current legal lists rule has a weakness as it does not permit the trustee’s broad discretion, and it is not in the best interest for the beneficiaries in the sense of the protection of the beneficiary’s wealth. Thus, this article finds that the current legal list rule should be abolished. Furthermore, this paper recommends the legislators to adopt the Prudent Investor Rule including a duty to diversify.