Presentation on theme: "Performance Calculations 101 Monday, October 19, 2009 Public Pension Financial Forum John D. Simpson, CIPM The Spaulding Group, Inc."— Presentation transcript:
Performance Calculations 101 Monday, October 19, 2009 Public Pension Financial Forum John D. Simpson, CIPM The Spaulding Group, Inc.
What we’ll do today We’ll cover a few basic formulas that are used to calculate rates of return and risk “Nature is pleased with simplicity” Issac Newton, Principia We will try to make this easy to comprehend But, we have a fair amount to cover and limited time Feel free to ask questions
Rates of Return: Time-weighting vs. Money-weighting Time-weighted returns measure the performance of the portfolio manager Money-weighted returns measure the performance of the fund or portfolio
Time-weighting Time-weighting eliminates or reduces the impact of cash flows Because managers don’t control the flows Two general approaches: Approximations, which approximate the exact, true, time-weighted rate of return Exact, true, time-weighted rate of return
Approximation methods we’ll discuss Original Dietz Modified Dietz Modified BAI (a.k.a. Modified IRR and Linked IRR)
What Are Cash Flows? Two types: External: impact the portfolio Internal: impact securities, sectors Specifics: External: contributions/withdrawals of cash and/or securities Internal: buys/sells, interest/dividends, corporate actions
The scenario we will use to demonstrate the various formulas:
Assumes constant rate of return on the portfolio during the period Very easy method to calculate Provides approximation to the true rate of return Returns can be distorted when large flows occur Also, return doesn’t take into account market volatility, which further affects the accuracy Weights each cash flow as if it occurred at the middle of the time period Original Dietz
Modified Dietz Method Assumes constant rate of return on the portfolio during the period Provides an improvement in the approximation of true time-weighted rate of return, versus the Original Dietz formula Disadvantage greatest when: (a) 1 or more large external cash flows; (b) cash flows occur during periods of high market volatility Weights each external cash flow by the amount of time it is held in the portfolio
Modified Dietz Method
Determines internal rate of return for the period Takes into account the exact timing of each external cash flow Market value at beginning of period is treated as cash flow Disadvantage: Requires iterative process solution – difficult to calculate manually Modified BAI (Modified IRR, Linked IRR)
Modified BAI Method
Value portfolio every time external flows occur Advantage: calculates true time-weighted rate of return Disadvantage: requires precise valuation of the portfolio on each day of external cash flow True, exact TWRR
Money-weighted returns Internal Rate of Return (IRR) Takes cash flows into consideration Cash flows will impact the return Only uses cash flows and the closing market value in calculation (don’t revalue during period) Produces the return that equates the present value of all invested capital
It’s an iterative process We solve for r, by trial-and error The general rule is to use the Modified Dietz return as the “first order approximation” to the IRR Solving for the IRR
Why did the Modified BAI and IRR yield the same returns (2.63%)? Calculation Question
Contrasting IRR with time-weighting IRR values portfolio at the beginning and end of the period TWRR values at various times throughout the period
Our investment is a mutual fund Where two investors begin with 100 shares And both make two additional purchases during the year of 100 shares each But at different times And at different prices We’ll use an example to compare TWRR and MWRR
Paper gain of $600! Paper loss of $600! The investments’ unrealized gains/losses
The fund’s return (using an exact TWRR method): What’s our return?
How about our investors? But this investor lost $600 And this investor made $600 Because time weighting eliminates the effect of cash flows!
Investor #1’s IRR = % Investor #2’s IRR = % How about money-weighting?
As a Plan Sponsor … Which returns make more sense to you? Which are more meaningful? TWRR judges portfolio manager MWRR judges the portfolio
Multi-period rates of return We don’t just want to report returns for a month We want to link our returns to form quarterly, annual, since inception, etc. returns How do we do this?
The process used to link sub-period returns to create returns for extended periods: e.g., We want to take January, February, and March returns to create a return for 1Q We geometrically link in order to compound our returns Geometric linking
Step-by-step process: 1.Convert the returns to a decimal 2.Add 1 3.Multiply these numbers 4.Subtract 1 5.Convert the number to a percent Geometric linking
Before we move to risk, are there any questions?
Risk measures Two categories Formulas that measure risk We’ll look at standard deviation and tracking error Formulas that adjust the return per unit of risk We’ll look at Sharpe Ratio and Information Ratio
Standard Deviation Measures volatility of returns over time The most common and most criticized measure to describe the risk of a security or portfolio. Used not only in finance, but also statistics, sciences, and social sciences. Provides a precise measure of the amount of variation in any group of numbers.
Standard Deviation; based on the Bell-shaped (normal) curve
Standard Deviation Formulas Note: This is represented in Excel as the STDEVP Function Note: This is represented in Excel as the STDEV Function
An example of standard deviation
Tracking Error The difference between the performance of the benchmark and the replicating portfolio Measures active risk; the risk the manager took relative to the benchmark Measured as annualized standard deviation Standard deviation of excess returns Standard deviation of the difference in historical returns of a portfolio and its benchmark
Tracking Formula: Volatility of Past Returns vs. Benchmark Tracking error measures how closely the portfolio follows the index and is measured as the standard deviation of the difference between the portfolio and index returns.
An example of Tracking Error To annualize, multiply by square root of 12
The Sharpe Ratio Also known as Reward-to-Variability Ratio Developed by Bill Sharpe – Nobel Prize Winner Equity Risk Premium (Return) / Standard Deviation (Risk)
Sharpe Ratio Formula Equity Risk Premium divided by standard deviation of portfolio returns
An example of Sharpe Ratio To annualize, multiply by square root of 12
Information Ratio The Information Ratio measures the excess return of an investment manager divided by the amount of risk the manager takes relative to the benchmark It’s the Excess Return (Active Return) divided by the Tracking Error (Active Risk) IR is a variation of the Sharpe Ratio, where the Return is the Excess Return and the Risk is the Excess or Active Risk
Information Ratio IR serves as a measure of the “special information” an active portfolio manager has Value Added (excess return) / Tracking Error Typically annualize
Information Ratio Active Return on the account Account’s Active Risk
An example of Information Ratio
What have we covered today Hopefully you’ll agree a lot in a short time Return measures TWRR approximation measues Original Dietz Modified Dietz Modified BAI TWRR exact measure True daily Geometric Linking
What have we covered today Risk measures Measurements of risk Standard deviation Tracking error Measurements of risk-adjusted returns Sharpe ratio Information ratio