Viceira, Luis M., (May 2007)Abstract:This paper reviews recent advances in academic models of asset allocation for long-term investors, and explores their implications for the design of investment products that help investors save for retirement, particularly life-cycle funds and life-style (or balanced) funds. The paper argues that modern portfolio theory provides scientific foundation for the "risk-based" asset allocation strategies and the "age-based" asset allocation strategies that characterize life-style and life-cycle funds. Risk-based allocation strategies can be optimal in an environment where investors face real interest rate (or reinvestment risk), while human wealth considerations give rise to horizon effects in asset allocation. However, this theory also makes a number of suggestions about how life-style and life-cycle funds should be structured, and shows for which types of investors these funds are appropriate investment choices. Thus, modern portfolio theory provides only qualified support for these funds. Nevertheless, the paper argues that properly designed life-cycle funds are better default investment choices than money market funds in defined-contribution pension plans. The paper also argues for the creation of life-cycle funds that allow for heterogeneity in risk tolerance, and for the creation of life-cycle funds specific to defined-contribution plans that can better account for the correlation between human capital and stock returns. It also suggests that investors who expect to receive Social Security benefits and pension income after retirement should choose a target retirement date for their funds based on their life-expectancy, not their expected retirement date.
Making Investment Choices as Simple as Possible: An Analysis of Target Date Retirement Funds
by Bodie, Zvi and Treussard, Jonathan (January 2007)Abstract:Many participants in self-directed retirement plans (401k, IRA, etc.) do not know enough about investing to choose rationally among alternatives. Others may know enough, but find it unpleasant or too time-consuming. Target-date funds (TDFs), also known as life-cycle funds, are being offered as a simple solution to their dilemma. A TDF is a "fund of funds" diversified across stocks, bonds, and cash with the feature that the proportion invested in stocks is automatically reduced as time passes. Empirical evidence suggests that a simple TDF strategy would be an improvement over the choices currently made by many uninformed plan participants. This paper explores one way to achieve an even greater improvement. Using a compact continuous-time optimization model, we characterize a person for whom a TDF strategy would be optimal: a "natural TDF holder." We then show that the TDF strategy may be far from optimal for people who — although of the same age — differ from the natural TDF holder in their risk aversion or exposure to human-capital risk. To bring such plan participants much closer to their optimal strategy it is enough to add a second simple investment alternative — a safe fund matched to their time horizon. Participants with the same time horizon could then choose (or be advised to choose) either the TDF or the safe target-date fund depending on their risk aversion and human-capital risk. We find that people who are very risk averse and who have a high exposure to market risk through their labor income would experience a substantial gain in welfare from being offered a safe target-date fund rather than a risky one. Recent empirical research suggests that human-capital betas change over one's working career. They are typically quite high during the early years when human capital represents the largest part of total wealth for most people, and they decline with age. To reflect gradual changes in human capital risk over the life-cycle from predominantly "stock-like" to mostly "bond-like," TDFs should switch from a "linear" strategy to a "hump-shaped" strategy with respect to age.
Popping The Hood: An Analysis of Major Life Cycle Fund Families
A study of major fund family life cycle funds from Turnstone Advisory Group LLC.