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CHAPTER EIGHTEEN. PORTFOLIO PERFORMANCE EVALUATION. MEASURES OF RETURN. MEASURES OF RETURN complicated by addition or withdrawal of money by the investor percentage change is not reliable when the base amount may be changing timing of additions or withdrawals is important to measurement.
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CHAPTER EIGHTEEN PORTFOLIO PERFORMANCE EVALUATION
MEASURES OF RETURN • MEASURES OF RETURN • complicated by addition or withdrawal of money by the investor • percentage change is not reliable when the base amount may be changing • timing of additions or withdrawals is important to measurement
MEASURES OF RETURN • TWO MEASURES OF RETURN • Dollar-Weighted Returns • uses discounted cash flow approach • weighted because the period with the greater number of shares has a greater influence on the overall average
MEASURES OF RETURN • TWO MEASURES OF RETURN • Time-Weighted Returns • used when cash flows occur between beginning and ending of investment horizon • ignores number of shares held in each period
MEASURES OF RETURN • TWO MEASURES OF RETURN • Comparison of Time-Weighted to Dollar-Weighted Returns • Time-weighted useful in pension fund management where manager cannot control the deposits or withdrawals to the fund
MAKING RELEVANT COMPARISONS • PERFORMANCE • should be evaluated on the basis of a relative and not an absolute basis • this is done by use of a benchmark portfolio • BENCHMARK PORTFOLIO • should be relevant and feasible • reflects objectives of the fund • reflects return as well as risk
THE USE OF MARKET INDICES • INDICES • are used to indicate performance but depend upon • the securities used to calculate them • the calculation weighting measures
THE USE OF MARKET INDICES • INDICES • Three Calculation Weighting Methods: • price weighting • sum prices and divided by a constant to determine average price • EXAMPLE: THE DOW JONES INDICES
THE USE OF MARKET INDICES • INDICES • Three Calculation Weighting Methods: • value weighting (capitalization method) • price times number of shares outstanding is summed • divide by beginning value of index • EXAMPLE: • S&P500 • WILSHIRE 5000 • RUSSELL 1000
THE USE OF MARKET INDICES • INDICES • Three Calculation Weighting Methods: • equal weighting • multiply the level of the index on the previous day by the arithmetic mean of the daily price relatives • EXAMPLE: • VALUE LINE COMPOSITE
ARITHMETIC V. GEOMETRIC AVERAGES • GEOMETRIC MEAN FRAMEWORK GM = (P HPR)1/N - 1 where P = the summation of the product of HPR= the holding period returns n= the number of periods
ARITHMETIC V. GEOMETRIC AVERAGES • GEOMETRIC MEAN FRAMEWORK • measures past performance well • represents exactly the constant rate of return needed to earn in each year to match some historical performance
ARITHMETIC V. GEOMETRIC AVERAGES • ARITHMETIC MEAN FRAMEWORK • provides a good indication of the expected rate of return for an investment during a future individual year • it is biased upward if you attempt to measure an asset’s long-run performance
RISK-ADJUSTED MEASURES OF PERFORMANCE • THE REWARD TO VOLATILITY RATIO (TREYNOR MEASURE) • There are two components of risk • risk associated with market fluctuations • risk associated with the stock • Characteristic Line (ex post security line) • defines the relationship between historical portfolio returns and the market portfolio
TREYNOR MEASURE • TREYNOR MEASURE • Formula where arp = the average portfolio return arf = the average risk free rate bp= the slope of the characteristic line during the time period
TREYNOR MEASURE THE CHARACTERISTIC LINE SML arp bp
TREYNOR MEASURE • CHARACTERISTIC LINE • slope of CL • measures the relative volatility of portfolio returns in relation to returns for the aggregate market, i.e. the portfolio’s beta • the higher the slope, the more sensitive is the portfolio to the market
TREYNOR MEASURE THE CHARACTERISTIC LINE SML arp bp
THE SHARPE RATIO • THE REWARD TO VARIABILITY (SHARPE RATIO) • measure of risk-adjusted performance that uses a benchmark based on the ex-post security market line • total risk is measured by sp
THE SHARPE RATIO • SHARPE RATIO • formula: where SR = the Sharpe ratio sp = the total risk
THE SHARPE RATIO • SHARPE RATIO • indicates the risk premium per unit of total risk • uses the Capital Market Line in its analysis
THE SHARPE RATIO CML arp sp
THE JENSEN MEASURE OF PORTFOLIO PERFORMANCE • BASED ON THE CAPM EQUATION • measures the average return on the portfolio over and above that predicted by the CAPM • given the portfolio’s beta and the average market return
THE JENSEN MEASURE OF PORTFOLIO PERFORMANCE • THE JENSEN MEASURE • known as the portfolio’s alpha value • recall the linear regression equation y = a + bx + e • alpha is the intercept
THE JENSEN MEASURE OF PORTFOLIO PERFORMANCE • DERIVATION OF ALPHA • Let the expectations formula in terms of realized rates of return be written • subtracting RFR from both sides
THE JENSEN MEASURE OF PORTFOLIO PERFORMANCE • DERIVATION OF ALPHA • in this form an intercept value for the regression is not expected if all assets are in equilibrium • in words, the risk premium earned on the jth portfolio is equal to bj times a market risk premium plus a random error term
THE JENSEN MEASURE OF PORTFOLIO PERFORMANCE • DERIVATION OF ALPHA • to measure superior portfolio performance, you must allow for an intercept a • a superior manager has a significant and positive alpha because of constant positive random errors
COMPARING MEASURES OF PERFORMANCE • TREYNOR V. SHARPE • SR measures uses s as a measure of risk while Treynor uses b • SR evaluates the manager on the basis of both rate of return performance as well as diversification
COMPARING MEASURES OF PERFORMANCE • for a completely diversified portfolio • SR and Treynor give identical rankings because total risk is really systematic variance • any difference in ranking comes directly from a difference in diversification
CRITICISM OF RISK-ADJUSTED PERFORMANCE MEASURES • Use of a market surrogate • Roll: criticized any measure that attempted to model the market portfolio with a surrogate such as the S&P500 • it is almost impossible to form a portfolio whose returns replicate those over time • making slight changes in the surrogate may completely change performance rankings
CRITICISM OF RISK-ADJUSTED PERFORMANCE MEASURES • measuring the risk free rate • using T-bills gives too low of a return making it easier for a portfolio to show superior performance • borrowing a T-bill rate is unrealistically low and produces too high a rate of return making it more difficult to show superior performance