Wednesday 14 January 2009

Portfolio Theory: Market Risk Premiums

Market Risk Premiums

The variables also are integrated so that changes in one may indicate modification of another. For example, increases in the risk-free rate entail decreases in the market risk premium (the latter supposedly measures the difference between the risk-free rate and the expected return on common stocks). The need for estimation judgment, and the complex interrelationship among these variables, means that prudent analysis draws on multiple reasonable data points (by applying alternative methods and taking alternative measures of each variable).

The “market risk premium: is a guess based on history of what special inducements it takes to attract investors into stocks rather than buying U.S. Treasury securities or alternative investments. The idea is that investors must be given special compensation to bear the special risks of stocks or else they will not invest in them.

Data on Market Risk Premiums

Common practice is to consult data books published by leading economists, such as the one published by a firm run by Yale University professor Roger Ibbotson called the Ibbotson & Sinquefeld Yearbook. The harder way is doing it yourself, which is virtually impossible for non-professionals. But it is useful to understand why, so here goes.

Market risk premium data can be calculated up-to-the-minute at any time. Three crucial assumptions must be made to estimate the market risk premium.
1. First, the estimator must choose either historical data or some measure of future performance.
2. Second, one must define a “market” for the measure, such as the Standard & Poor’s 500, the New York Stock Exchange as a whole, or some other index.
3. Third, the estimate is based on a specified time period.

Alternatives include the period from the late 1800s (when market data were first recorded) to the time of valuation interest; from 1926 (when the University of Chicago began a database, thought to have the virtue of including a full business cycle before the 1929 market crash) to the time of valuation interest; for the 30-year period before the time of valuation interest (reflecting business cycles exhibiting more relevant business and financial risks and factors); or for specific environments being analysed, such as the early 2000s.

Challenges in using "market risk premium"

Seizing on a measure of the “market risk premium” became acutely tricky during the late 1990s because any such thing seemed to be evaporating. Any premium that once existed – e.g., in the period before 1990 – dwindled toward zero, as the most powerful bull market in world history produced investors who needed no inducements to join. Even staunch devotees of modern finance theory lamented the declining usefulness of “market risk premium” device during the 1990s.

Despite this well-known fact even among its fans, analysts sticking with this learning adhere to favourite benchmarks, such as 9 percent based on long-run historical returns on stocks dating back to the 1930s. Others respond to their gut sense that this is almost certainly wrong, and opt instead for rates of 7 percent, 5 percent, or less. Some believe it was moving towards zero in the late 1990s.

A group of the country’s leading financial economists assembled in mid-2000 to offer their measurements of the market risk premium. Eleven participated. Their estimates of the risk premium were: 0, 1-2, 3, 3-4, 4, 6, 6, and 8.1 percent, with three refusing to venture a guess giv en the concept’s indefiniteness and uncertain reliability.

Reasons for the decline or evaporation include powerful forces, such as U.S. investors became more long-term oriented, U.S. business efficiency heightened, fiscal policies and monetary management improved, capitalism spread globally, wealth increased, and business fundamentals exhibited less volatility.


Also read:
  1. Understanding Discount Rates
  2. Risk-free rate
  3. Traditional Method: Discount rate or WACC (I)
  4. Traditional Method: Discount rate or WACC (II)
  5. Modern Portfolio Theory
  6. Portfolio Theory: Market Risk Premiums
  7. Portfolio Theory: Beta
  8. Is the market efficient, always?
  9. Discount Rate Determinations: Summary

No comments: