Portfolio Optimizers:
The Road to Financial Security or the Primrose Path? |
Author
Richard D. Glass
Stan Marshall
Published in
Personal Finances and Worker Productivity
June 1999, Volume 3, Number 1
Virginia Polytechnic Institute
and State University |
Recently
Charles Schwab aired an advertisement that portrayed a couple in their fifties explaining
why they hired an investment advisor. Their reasoning was simple. Although investing is
important, it is also boring and confusing. Since life is already sufficiently hectic,
there is no reason to spend precious time learning about this dismal topic when you can
hire a professional to do it for you.
That large numbers of participants invest blindly
and need help in determining their asset allocations is widely accepted. A recent EBRI
study 1 found that 45% of all workers have never determined their retirement
income needs. John Hancocks Fifth Defined Contribution Plan Survey 2
showed just how little participants, even the college educated ones, know about investing.
For example, 47% and 49% of the participants thought stocks and bonds could be found in
money market funds respectively. Only 25% of the participants knew that the best time to
transfer money into bond funds is when interest rates are expected to decrease.
Many plan sponsors believe that the vast majority
of their 401(k) plan participants are unwilling to take the time to become knowledgeable
about investing. This ignorance prevents participants from making informed asset
allocation decisions and then monitoring their choices. These plan sponsors believe that
participants want to be told how to invest their account balances. Companies that market
asset allocation services to plan participants (with the endorsement of plan fiduciaries)
have been formed to meet this perceived pent-up demand.
However, the fact that large institutional
investors find value in hiring consultants to perform (and then explain) asset allocation
studies does not necessarily mean participants will benefit from an apparently similar
service. These services are based on mathematical models (portfolio optimizers), and, like
any model, they have limitations. If participants dont understand these limitations
(and they probably are not even aware that these limitations exist), they can easily
misinterpret the results and overestimate the models presumed predictive power.
The testimony to the limitations and
uncertainties of optimizers came from Harry Markowitz himself when he discussed how he
invests his retirement money:
"I should have computed the historical
covariances of the asset classes and drawn an efficient frontier. Instead, I visualized my
grief if the stock market went way up and I wasnt in itor if it went way down
and I was completely in it. My intention was to minimize my future regret. So I split my
contributions fifty-fifty between bonds and equities." 3
Sophisticated institutional investors realize
that optimizers are just another tool to be used in the process of developing an asset
allocation. Unknowledgeable participants, on the other hand, will likely base their
decisions solely on the recommendations without considering the very real possibility that
the future will not be a rosy as the optimizer assumed it would be. This danger creates a
fiduciary liability quagmire for the plan sponsor which appears to more than offset any
benefit to the participants.
Plan sponsors want their employees to have
financially secure retirements. However, plan sponsors cannot change the fact that there
is no "one-minute" answer to the question: How should I invest my money?
Achieving retirement security requires the development and implementation of a sound
investment strategy that includes monitoring the asset allocation on an ongoing basis.
Participants must accept responsibility for their own retirement security. The only
alternative is to hope to get lucky.
Before providing or making available asset
allocation services to participants, plan fiduciaries must develop an understanding of
what portfolio optimization models can and cannot do. Only by undertaking this
intellectual exercise will the fiduciary gain the knowledge that will not only allow him
to make an informed judgement as to the merits of offering such services, but also enable
him to articulate his decision in a judicious fashion. The purpose of this article is to
outline the issues surrounding the advisability of offering asset allocation services to
participants.
Scientists develop models for several reasons.
Model building enables scientists to formalize their understanding of what they have
observed. They review observations, both their own and those of others, in order to create
a story (i.e., the hypothesis or model) that incorporates and explains known data and
apparent relationships. It is essential that the data used as the foundation for a model
be reproducible and predictable. If scientists cannot agree on the observations and
measurements that form the basis of a model, it is highly unlikely that the model will be
taken seriously.
Once a model is constructed, scientists have the
opportunity to assess both its robustness and shortcomings. One measure of robustness is
the degree to which new observations fit into the models framework. Another measure
is the number of and type of exceptions to the model. The identification and analysis of
exceptions is a valuable tool in the process of actually determining what is being
observed and discovering if the model should be refined, drastically altered, or scraped
altogether.
Another characteristic of a good model is its
predictive value. If the system is disturbed or altered in a well-defined manner, a very
specific outcome can often be foretold. Vaccinations are an example of this. Scientists,
by understanding the immune response, have learned how to make effective vaccines to a
wide variety of organisms. These vaccines protect practically all of us from everything
from specific flu viruses to tetanus and polio.
Other models forecast a range of outcomes and
assign, with a high degree of accuracy, specific probabilities to each of them. For
example, if the genetic makeup of a couple is known, a geneticist can predict the
likelihood that the couples next child will be a boy with brown eyes and blond hair
rather than a girl with green eyes and red hair.
Scientific models, then, attempt to describe
physical and biological processes and structure from various perspectives--causal, static,
and dynamic. Depending upon its degree of complexity, a model can attempt to explain what
is there today, how it got there, and how it will evolve in the future. Models can also
describe interrelationships with other objects or processes. Furthermore, the model can
provide insights into how the subject under study can be modified so that its usefulness
can be enhanced.
So what is portfolio
optimization and how does it fit into the concept of scientific modeling just discussed?
To begin with, portfolio optimization is a powerful tool for analyzing how the different
asset classes can interact with each other. Given a specific set of input data (each
utilized asset classs expected mean return and standard deviation and correlations
between the different asset classes) and constraints (limitations on amounts, if any, of
each asset class) the optimizer will identify the most efficient portfolio among the
universe of possible ones. "Most efficient portfolio" means the portfolio with
the highest return for the level of risk specified or the portfolio with the lowest risk
for the return specified.
Optimizers can generate a variety of reports
including the likelihood that a portfolio will generate a specified minimum return, the
magnitude of downside risk, the consequences of changing the constraints and/or adding or
deleting asset classes. Portfolio optimization is an invaluable tool by which an investor
can get an understanding of the investment process and the types of portfolios that may
meet her needs. In fact, the mathematical nature of portfolio optimization appears to
guarantee that all the requirements of a scientific model are met:
- a very formal and thorough understanding of a set
of relationships;
- a tool for analyzing interrelationships;
- the ability to ask and answer different questions;
- the ability to make quantifiable predictions (as
to portfolio returns and volatility).
A portfolio optimizer can indeed make detailed
predictions. However, the optimizers predictive ability must be broken down into two
components: the optimizers algorithms and the input data. For this section of the
discussion, it is assumed that the algorithms (i.e., mathematical rules) underlying
optimization models are sufficiently accurate to capture most real world situations. This
statement simply means that the optimizer is an efficient number crunching
machine--nothing more and nothing less.
(Scientific models are built so that they may be
tested. If the model correctly describes a process, such as mixing chemicals A and B under
a specified set of conditions, then the outcome of the reaction, chemical C, should be
generated regardless of where in the world this process is done. In addition, chemists
should be able to predict what products will be obtained if the conditions are changed
and/or other chemical substances are mixed with A and B. Structuring models in this way
allows the model itself to be tested. Unlike scientific models, however, portfolio
optimizers have no predictive value in and of themselves. Their usefulness is their
ability to manipulate data.)
A portfolio optimizers worth to the average
participant in a self-directed retirement plan, then, is its predictive value, and that is
a function of the data it is crunching. The key questions are:
- Will the future behavior of the asset classes have
any correlation to the data that is inputted into the optimizer?
- How much error in the input data (i.e., the
difference in values of the projected versus actual means, standard deviations, and
correlations) can the optimizer tolerate before its predictions become meaningless from a
decision making perspective?
Unfortunately a major weakness of optimization
models can be summarized by the old adage, "garbage in, garbage out."
Tables 1 and 2 show just how unreliable
historical data can be when used to make predictions about future asset class returns. For
example, Table 1 shows that for the ten year period from 1949 through 1958 (row two in the
table), the S&P 500 had an annualized compound return of 20.06%. In the succeeding ten
years (1959 through 1968, row three), however, the S&P 500 had a return of only half
that amount (10.00%) representing a change in return of 10.6%. The last row of Table 1
shows the average magnitude of the changes in returns from each ten year period to the
next.
Because timing (the length of the holding periods
as well as the starting and ending years) can have an impact on studies like the one shown
in Table 1, several similar studies were also done using different time periods. Tables 2a
and 2b are a summary of these studies and clearly shows that the variation in returns from
one period to the next can be observed regardless of the time period used.
Table 1: Annualized Compound Returns for
Successive 10 Year Periods
|
|
|
|
|
|
|
|
|
Ibbotson |
Ibbotson |
|
|
|
Ibbotson |
Int.-term |
One
Year |
|
Period |
S&P
500 |
Small
Stocks |
Govt
Bonds |
Govt
Bonds |
T-bills |
 |
1939-1948 |
7.26% |
18.57% |
2.04% |
0.69% |
0.30% |
1949-1958 |
20.06% |
17.23% |
1.61% |
2.07% |
1.68% |
1959-1968 |
10.00% |
20.73% |
3.52% |
4.49% |
3.52% |
1929-1978 |
3.16% |
4.48% |
6.47% |
6.84% |
5.94% |
1979-1988 |
16.33% |
18.93% |
10.97% |
10.40% |
9.09% |
1989-1998 |
19.19% |
13.22% |
8.74% |
6.44% |
5.29% |
|
|
|
|
|
|
| Average
magnitude |
|
|
|
|
|
| of change
in return from |
9.15% |
8.25% |
2.40% |
2.73% |
2.52% |
| one period
to the next |
|
|
|
|
|
 |
Source: Stocks, Bonds, Bills, and Inflation
1999 Yearbook. Ibbotson Associates, Chicago (annually updates work by Roger G.
Ibbotson and Rex A. Sinquefield). Used with permission. All rights reserved.
For example, the results of the study shown in
Table 1 can be seen in the first row in Table 2a. For the successive 10 year periods
beginning in 1939 and ending in 1998 (1939-1948 followed by 1949-1958, etc.), the return
of the S&P 500 changed an average of 9.15% from one period to the next. The second row
of the table shows that for the successive 10 year periods beginning in 1938 and ending in
1997 (1938-1947 followed by 1948-1957, etc.), the return of the S&P 500 changed an
average of 6.83% from one period to the next.
Table 2b shows that the effects seen for 10 year
holding periods can also be observed for 5 year holding periods. The words of John Allen
Paulos seems to adequately summarize the observations shown in Tables 1, 2a, and 2b:
"Stock prices seem to obey the laws that govern random phenomena, so its fair to
infer that maybe theyre random." 4
Plan fiduciaries must ask: Will the inputs the
asset allocation service provider uses accurately reflect the investment environment of
the future? If the portfolio optimizers inputs represent the output of a lousy
crystal ball, is there any value to the average plan participant in the recommendations
generated? After all, the average participant wants advice, not a tool whose use requires
an informed and sophisticated investor and/or the help of a highly paid consultant.
Table 2a:
Summary of Studies of Changes in Return Between
Consecutive Ten-Year Time Periods
|
|
|
|
|
|
|
|
|
Average Magnitude of Change in Annualized |
|
|
Compound Returns from One Ten Year Period to the Next |
 |
 |
 |
|
Number
of |
|
|
Ibbotson |
Ibbotson |
|
|
Successive |
|
Ibbotson |
Int.-term |
One
Year |
|
Period |
Periods |
S&P
500 |
Small
Stocks |
Govt
Bonds |
Govt
Bonds |
T-bills |
 |
1939-1998 |
Six |
9.15% |
8.25% |
2.40% |
2.73% |
2.52% |
1938-1997 |
Six |
6.83% |
11.28% |
2.33% |
2.69% |
2.54% |
1937-1996 |
Six |
6.89% |
5.94% |
2.67% |
2.63% |
2.52% |
1936-1995 |
Six |
6.65% |
12.58% |
2.30% |
2.57% |
2.47% |
1935-1994 |
Six |
7.52% |
11.99% |
1.85% |
2.43% |
2.35% |
1934-1993 |
Six |
5.52% |
10.01% |
2.43% |
1.98% |
2.16% |
1933-1992 |
Six |
5.53% |
6.13% |
2.35% |
1.77% |
1.96% |
1932-1991 |
Six |
6.56% |
8.14% |
2.89% |
1.86% |
1.54% |
1931-1990 |
Six |
5.62% |
9.03% |
2.71% |
2.11% |
1.65% |
1930-1989 |
Six |
8.92% |
6.57% |
2.76% |
2.21% |
1.72% |
 |
Source: Stocks, Bonds, Bills, and Inflation
1999 Yearbook. Ibbotson Associates, Chicago (annually updates work by Roger G.
Ibbotson and Rex A. Sinquefield). Used with permission. All rights reserved.
Table 2b:
Summary of Studies of Changes in Return Between
Consecutive Five-Year Time Periods
|
|
|
|
|
|
|
|
|
Average Magnitude of Change in Annualized |
|
|
Compound Returns from One Five Year Period to the Next |
 |
 |
 |
|
Number
of |
|
|
Ibbotson |
Ibbotson |
|
|
Successive |
|
Ibbotson |
Int.-term |
One
Year |
|
Period |
Periods |
S&P
500 |
Small
Stocks |
Govt
Bonds |
Govt
Bonds |
T-bills |
 |
1934-1998 |
Thirteen |
6.17% |
15.41% |
1.86% |
1.64% |
1.43% |
1933-1997 |
Thirteen |
5.47% |
14.18% |
1.78% |
1.48% |
1.42% |
1932-1996 |
Thirteen |
8.37% |
18.42% |
3.14% |
1.57% |
1.28% |
1931-1995 |
Thirteen |
7.16% |
20.24% |
2.38% |
1.89% |
1.39% |
1930-1994 |
Thirteen |
8.42% |
15.15% |
2.54% |
1.88% |
1.50% |
 |
Source: Stocks, Bonds, Bills, and Inflation
1999 Yearbook. Ibbotson Associates, Chicago (annually updates work by Roger G.
Ibbotson and Rex A. Sinquefield). Used with permission. All rights reserved.
To get a better handle on this issue, it is
necessary to understand how institutional investors use portfolio optimization studies. To
begin with, sophisticated investors recognize how difficult it is to estimate the future
performance of the different asset classes over the next month, yet alone the next year or
the next five years. They understand why articles with titles like A D+ for the Dismal
Scientists? Even the Feds Gurus Often Goof and Dismal Days for the Dismal
Science are written. William A. Sherden has succinctly summed up the state of
predicting investment returns:
"Despite recent innovations in information
technology and decades of academic research, successful stock market prediction has
remained an elusive goal...Overall, we have not made progress in predicting the stock
market, but this has not stopped the investment business from continuing the quest, and
making $100 billion annually doing so."
Recent work by Meir Statman has also confirmed
how difficult it is to outsmart the capital markets. He found that there is a
statistically significant negative relationship between the sentiment of Wall
Street strategists and the returns of the S&P 500. There is also a negative
relationship between newsletter writers and future S&P 500 returns, but this
relationship is not statistically significant.
Before institutional investors develop their
asset allocations, they ask questions such as:
- When will small-cap stocks resurrect themselves?
- Has value investing gone the way of the dinosaur,
or is it in a state of prolonged hibernation?
- Are low inflation and low interest rates here to
stay? And, if so, how must the economic paradigm underlying the forecasting of the returns
of the different asset classes be changed?
- In a low inflation and a low interest rate
environment, are current P/E multiples reasonable?
If questions like these cannot be answered with
any degree of certainty, and they cannot, it is impossible to feed precise, perhaps even
reasonable, inputs into an optimizer. However, what can be done is to run various asset
class return scenarios through optimizers and analyze the outputs. These studies give the
informed institutional investor some idea of how, under each return scenario, their
portfolios will perform, and thus how their organizations needs will or will not be
fulfilled. Sophisticated institutional investors, then, use portfolio optimizers in the
hope of gaining additional insights and not to be told how to invest their funds.
In 1938 John Maynard Keynes expressed a similar
belief:
"It seems to me that economics is a branch
of logic...Progress in economics consists almost entirely in a progressive improvement in
the choice of models...But it is of the essence of a model that one does not fill in real
values for the variable functions. To do so would make it useless as a model...because,
unlike the typical natural science, the material to which it is applied is, in too many
respects, not homogenous through time...economics is essentially a moral science and not a
natural science. That is to say, it employs introspection and judgments of value."
That 401(k) participants are not interested in
such investment issues is universally accepted. They just want to earn the growth rate
(i.e., the compound annual rate of return) that a retirement planning calculator has
indicated is required to achieve their retirement security. Most participants have no idea
what portfolio optimizers or expected mean returns are, and furthermore, they do not care.
When a plan sponsor endorses (and permitting an
organization to solicit participants is an endorsement) a vendor of asset allocation
services, participants expect the advice they get to have value. Further, to participants,
"having value" means they can expect to achieve a sufficient growth rate if they
follow the experts advice (recommended contribution level and asset allocation).
This expectation should not be surprising. Most
communications materials are written at a junior high or lower level because investment
communicators maintain that participants cannot understand concepts like mean, standard
deviation, and correlation. If these concepts cannot be grasped, it is not reasonable to
expect participants to appreciate a more advanced concept like the probability of a
portfolio achieving a certain return. In fact, it is quite likely that most plan
fiduciaries, let alone participants, do not realize the magnitude of the difference that
can occur between an asset classs mean return and compound annual return during a
given period (Table 3).
Table 3: Mean versus Annualized Compound
Returns by Decade
|
|
|
|
|
|
|
|
|
|
Ibbotson |
|
|
|
|
Ibbotson |
Int.-term |
|
Period |
|
S&P
500 |
Small
Stocks |
Govt
Bonds |
T-bills |
 |
1930-1939 |
Mean Return |
5.34% |
15.39% |
4.64% |
0.56% |
|
Annualized
Compound Return |
-0.05% |
1.38% |
4.58% |
0.55% |
|
|
|
|
|
|
1940-1949 |
Mean Return |
10.30% |
25.30% |
1.83% |
0.41% |
|
Annualized
Compound Return |
9.17% |
20.69% |
1.83% |
0.41% |
|
|
|
|
|
|
1950-1959 |
Mean Return |
20.84% |
19.51% |
1.37% |
1.87% |
|
Annualized
Compound Return |
19.35% |
16.90% |
1.34% |
1.87% |
|
|
|
|
|
|
1960-1969 |
Mean Return |
8.69% |
19.32% |
3.54% |
3.89% |
|
Annualized
Compound Return |
7.81% |
15.53% |
3.48% |
3.88% |
|
|
|
|
|
|
1970-1979 |
Mean Return |
7.50% |
15.52% |
7.07% |
6.32% |
|
Annualized
Compound Return |
5.86% |
11.49% |
6.98% |
6.31% |
|
|
|
|
|
|
1980-1989 |
Mean Return |
18.19% |
17.00% |
12.17% |
8.92% |
|
Annualized
Compound Return |
17.55% |
15.83% |
11.91% |
8.89% |
|
|
|
|
|
|
1990-1998 |
Mean Return |
18.75% |
15.34% |
8.44% |
4.96% |
|
Annualized
Compound Return |
17.89% |
13.56% |
8.25% |
4.95% |
 |
Source: Stocks, Bonds, Bills, and Inflation
1999 Yearbook. Ibbotson Associates, Chicago (annually updates work by Roger G.
Ibbotson and Rex A. Sinquefield). Used with permission. All rights reserved.
When a plan sponsor makes available to
participants investment advice via an asset allocation service, care must be taken in
describing those services. Of course participants will be told that an expert is going to
advise them on what is the best or optimal portfolio for them based upon their own unique
circumstances. However, to protect themselves, plan sponsors must describe in unambiguous
detail the limitations of portfolio optimizers.
For example, Tables 4a and 4b show just how
sensitive optimizers are to inputs. The optimizer was programmed to create a portfolio
with an expected mean return of 10%. No constraints were put on the allocation, i.e.,
there were no ranges (minimum or maximum amounts) established for the five asset classes
used. Three sets of inputs were used. They were the historical data (returns, standard
deviations, and correlations) from three periods: 1926-1998, 1979-1998, and 1994-1998.
Table 4a: Portfolios Generated Targeting a 10%
Return*
|
|
|
|
|
|
|
|
|
|
|
Ibbotson |
Ibbotson |
|
|
Input |
|
Ibbotson |
Int.-term |
One
Year |
|
Portfolio |
Period |
S&P
500 |
Small
Stocks |
Govt
Bonds |
Govt
Bonds |
T-bills |
 |
A |
1926-1998 |
39.27% |
12.65% |
48.08% |
0.00% |
0.00% |
B |
1979-1998 |
20.11% |
0.00% |
0.00% |
42.10% |
37.79% |
C |
1994-1998 |
25.45% |
0.00% |
0.00% |
0.00% |
74.55% |
 |
*Portfolios generated using Ibbotson Optimizer
7.0 using the historical data shown in Table 4b and the correlations between the asset
classes as inputs.
Table 4b: Optimizer Inputs*
|
|
|
|
|
|
|
|
|
Percentage
of portfolio in each asset class |
 |
 |
 |
|
|
|
|
Ibbotson |
Ibbotson |
|
|
|
|
Ibbotson |
Int.-term |
One-Year |
|
Portfolio |
|
S&P 500 |
Small Stocks |
Govt Bonds |
Govt Bonds |
T-bills |
 |
A |
Mean Return |
13.17% |
17.39% |
5.47% |
4.74% |
3.82% |
|
Standard Deviation |
20.26% |
33.78% |
5.73% |
3.67% |
3.22% |
|
|
|
|
|
|
|
B |
Mean Return |
18.45% |
17.58% |
10.09% |
8.47% |
7.21% |
|
Standard Deviation |
13.08% |
18.90% |
7.43% |
3.72% |
3.01% |
|
|
|
|
|
|
|
C |
Mean Return |
24.75% |
14.13% |
6.47% |
5.64% |
4.96% |
|
Standard Deviation |
14.16% |
16.44% |
8.34% |
1.95% |
0.65% |
 |
*The correlations between the asset classes are
also used as optimizer inputs but are not shown here.
As can be seen in Table 4a, the resulting three
asset allocations differ dramatically. To some plan sponsors and participants, the
allocations might even be unacceptable for of lack of sufficient diversification due to
the exclusion of certain asset classes or the overweighting of others. "Is it prudent
for a 30 year old to put almost 75% of her money in T-bills? Or "does it make sense
to exclude small-cap stocks?" are just two questions that immediately pop-up.
These questions raise the issue if ranges should
be specified for the different asset classes. Other questions arise, such as: What percent
of the allocation should result from unemotional mathematics versus what percent should
come from human judgement? Who are the individuals who are creating the constraints? Is
human judgement the fine tuning device or is the optimizer the tuner? If the answer is the
latter, is the use of the optimizer justified when its limitations are considered?
Two other obvious questions are: Which data set
makes the most sense to use?; and How does the expert arrive at her inputs? After all, the
inputs are the experts prediction of the future, and in todays world of global
economic restructuring, can one realistically hope to glean from the past much insight
about the future.
Tables 5a and 5b show the sensitivity of
optimizers to even slight changes in inputs. Portfolio B is the optimal portfolio based on
the historical data from 1979 to 1998. The inputs for Portfolios D and E are the same as B
except that the expected mean return for the S&P 500 are increased and decreased by 1
percent respectively. Portfolios F and G also have the same inputs as A except that the
expected mean return for one-year government bonds are increased and decreased by 1%
respectively.
Table 5a shows that even a 1% change in the
expected mean return of an asset class can have a dramatic effect on the output of an
optimizer. Table 5b goes on to show that a variation in return for a single year (1995)
can cause such a change. Almost any participant, and probably most plan sponsors, would be
surprised at how these changes in input dramatically affect the allocations generated by
optimizers.
Table 5a: Sensitivity of Optimizer to Inputs*
|
|
|
|
|
|
|
|
|
Percentage
of portfolio in each asset class |
 |
 |
 |
|
|
|
|
Ibbotson |
Ibbotson |
|
|
|
|
Ibbotson |
Int.-term |
One-Year |
|
Portfolio |
Inputs Used |
S&P 500 |
Small Stocks |
Govt Bonds |
Govt Bonds |
T-bills |
 |
B |
1979-1998 |
20.11% |
0.00% |
0.00% |
42.10% |
37.79% |
|
|
|
|
|
|
|
D |
Increasing S&P 500 |
|
|
|
|
|
|
expected mean by 1% |
19.54% |
0.00% |
0.00% |
31.72% |
48.75% |
E |
Decreasing S&P 500 |
|
|
|
|
|
|
expected mean by 1% |
20.57% |
0.00% |
0.00% |
54.43% |
25.00% |
|
|
|
|
|
|
|
F |
Increasing One-Year |
|
|
|
|
|
|
Government Bonds |
|
|
|
|
|
|
expected mean by 1% |
14.04% |
0.00% |
0.00% |
53.56% |
32.39% |
G |
Decreasing One-Year |
|
|
|
|
|
|
Government Bonds |
|
|
|
|
|
|
expected mean by 1% |
23.52% |
0.00% |
5.03% |
0.00% |
71.45% |
 |
*Portfolios generated using Ibbotson Optimizer
7.0
Table 5b: Sensitivity of Optimizer to Returns
in a Single Year*
|
|
|
|
|
|
|
|
Annual |
Modified |
|
|
Annual |
Modified |
|
S&P 500 |
S&P 500 |
|
|
S&P 500 |
S&P 500 |
Year |
Returns |
Returns |
|
Year |
Returns |
Returns |
 |
1979 |
18.44% |
18.44% |
|
1989 |
31.49% |
31.49% |
1980 |
32.42% |
32.42% |
|
1990 |
-3.17% |
-3.17% |
1981 |
-4.91% |
-4.91% |
|
1991 |
30.55% |
30.55% |
1982 |
21.41% |
21.41% |
|
1992 |
7.67% |
7.67% |
1983 |
22.51% |
22.51% |
|
1993 |
9.99% |
9.99% |
1984 |
6.27% |
6.27% |
|
1994 |
1.31% |
1.31% |
1985 |
32.16% |
32.16% |
|
1995 |
37.43% |
17.25% |
1986 |
18.47% |
18.47% |
|
1996 |
23.07% |
23.07% |
1987 |
5.23% |
5.23% |
|
1997 |
33.36% |
33.36% |
1988 |
16.81% |
16.81% |
|
1998 |
28.58% |
28.58% |
|
|
|
|
|
|
|
|
|
|
|
Mean |
18.45% |
17.45% |
 |
*Portfolios generated using Ibbotson Optimizer
7.0
"If it is so difficult to predict future
asset class returns, and if the allocations generated by optimizers are so sensitive to
their inputs, how much value can we realistically expect to get from a portfolio
optimizer?" is the question all plan sponsors should ask before employing an asset
allocation service provider. They should recall John Bogles conclusion that
"There is no evidence in the record of mutual fund managers showing that they have
improved their performance by anticipating market changes and changing their cash
positions."
Unfortunately it is all to easy to dismiss the
above discussion as alarmist humbug. After all, Nobel prizes were awarded to Harry
Markowitz and William Sharpe for their work in laying the foundations of modern portfolio
theory, and both these men are actively involved in bringing asset allocation services to
plan participants.
Before pooh-poohing these concerns, plan sponsors
must ask three questions. The first one is: How bad can the recommendations of an asset
allocation service be in a bull market? The answer is probably not bad at all. In bull
markets it is difficult to botch up. Following the winners, diversifying some, and
increasing contributions are the ingredients of a winning formula for investment success.
How much money can a participant lose due to the
advice he received during a bear or a highly volatile and apparently trendless market is
the second, and much more important, question. The current bull market has been around for
years so the inexperienced participant cannot imagine what her emotions will be like when
returns stagnate or start falling with no end in sight. At that time participants will
ask: Why am I in stocks (or bonds), and why should I stay in them when they are losing
money?
Perhaps the most important question is: If
participants start to retire without sufficient nest-eggs, and they have religiously
followed the recommendations of the asset allocation vendor, will the vendor and/or plan
sponsor be held liable?
Winning Noble prizes for developing investment
theory does not guarantee the ability to exploit that theory in the real world. Long Term
Capital and its two Noble laureates amply demonstrated that. When all is said and done,
perhaps the most fundamental issue underlying offering asset allocation services is this:
Why does a plan sponsor feel that a highly sophisticated methodology used to show how
portfolios will react under different economic scenarios can be converted into a highly
reliable forecasting tool?
Asset allocation vendors dont own the goose
that lays the golden eggthe perfect optimizer. There is a vast chasm between what
portfolio optimization models are and what participants, vendors, and plan sponsors want
them to be. Plan sponsors should not provide participants with advice before exploring the
value and the accuracy of that advice. Ironically just reading the financial press will
make anyone suspicious of those who feel they can size-up the future. If optimizers blow
up like portfolio insurance did, lawsuits will abound.
Imagine a participants attorney asking
representatives of both the asset allocation vendor and plan sponsor questions such as:
1. If asset allocation methodology is so well
established, as suggested by your marketing materials, could you explain why Clements and
Hendry wrote in the preface to their book, Forecasting Economic Time Series,
"Our focus on forecasting began in 1991 when
Dave Hendry...found a dearth of theory to explain the systematic mis-forecasting that had
occurred in the mid and late 1980s. The literature on statistical forecasting also argued
that there was a marked discrepancy between theory and practice...
To deliver relevant conclusions about
macroeconomic forecasting, analyses must be based on assumptions pertinent to the
economies to be forecast. This forces the analysis to contend with non-constant, evolving
processes for which estimated econometric models are far from being facsimiles. It
transpires that conclusions which can be established formally for constant-parameter
stationary processes and correctly specified models often do not hold when those
unrealistic assumptions are relaxed."
2. Your recommendations are based upon (a) your
asset allocation model which you believe can model the real world and (b) the
appropriateness of your data inputs. Your model is based upon mean-variance optimization
(which assumes returns are normally distributed), but the returns of many of our
investment options do not have normal distributions (see the example in Figure 1). How is
your model affected when the returns of the funds you are optimizing are skewed, sometimes
considerably?
Figure 6: Scudder Income Fund Monthly Returns
(April 1991 to December 1996)

Source: Figure 6 is based on an excerpt from The
Streetlight Syndrome: Old and New Ways of Thinking About Risk presented by Phil
Fortuna of Scudder Kemper Investments at the Using Behavioral Finance to Improve
Investment Decisions Conference (Association for Investment Management and Research,
1999). Used by permission.
3. Does the use of portfolio optimizers offer any
real advantages to asset allocation over the common sense approach Ben Graham advocated
years ago in The Intelligent Investor?
"We have suggested as a fundamental guiding
rule that the investor should never have less than 25% or more than 75% of his funds in
common stocks, with a consequent inverse range between 75% and 25% in bonds. There is an
implication here that the standard division should be an equal one, or 50-50...
...For reasons already given we feel that the
defensive investor cannot afford to be without an appreciable proportion of common stocks
in his portfolio, even if he must regard them as the lesser of two evilsthe greater
being the risks attached to an all bond portfolio."
4. Why do you feel that you can predict with a
high degree of accuracy the future returns of the different asset classes? After all,
Werner De Bondt has shown that even economists have no insight into the future. Robert
Shiller has also shown that much of the S&P 500s return comes, not from
fundamentals, but from human emotion. Are you playing market psychiatrist?
5. What will be the recommended holding time for
each allocation6 months, 1 year, 5 yearsor will the holding period fluctuate
depending upon conditions?
6. How do you differentiate noise in the market
from the beginnings of new trends? How do you differentiate your process from market
timing or tactical asset allocation?
7. What percent of your models output is a
product of algorithms you follow slavishly and what percent is based upon human judgement?
Can this ratio change? How is the ratio determined?
So far this paper has centered on the inputs that
describe the asset classes and the investment options from which a participant builds his
portfolioexpected mean returns, standard deviations, and correlations. Another input
that goes into creating the recommended asset allocation is the participants risk
tolerance level.
A participants risk tolerance is suppose to
be determined by her score on a questionnaire. Once a participants risk tolerance
level is known, according to theory, it is possible to select the appropriate portfolio
among those that lie on a previously constructed efficient frontier. Participants like
this approach because it relieves them of the responsibility of making investment
decisions. In fact, they feel that their investment portfolio has been constructed in a
scientific fashion by experts.
Unfortunately this approach is not as clean as it
appears (to the eyes of participants and many plan sponsors). Some of the many questions
that must be answered are:
- Since each vendor uses its own risk tolerance
questionnaire, and these questionnaires vary quite a bit (both in number and types of
questions), what is the likelihood that these different questionnaires will arrive at the
same or similar risk tolerance level for a given participant? Which questionnaire, then,
is the most accurate in its assessment?
- What is the conceptual basis underlying your risk
tolerance questionnaire? Who developed the questionnaire and what are their backgrounds?
Are there other approaches to developing risk tolerance questionnaires? What are their
advantages? What results do they generate?
- How should a persons risk tolerance level be
defined? Can it really be determined?
- Does a persons risk tolerance level change
over time and if so, how often should it be recalculated?
- Is a persons answer to a question a function
of how the question is framed? For example, "Can you emotionally tolerate a drop of
15% in your account?" versus "As a long term investor, is a paper loss of 15% a
concern to you if you feel that the loss will be recouped in 3 or 4 months?"
- Which measurement of risk should the risk
tolerance questionnaire assessstandard deviation, downside risk, the likelihood of
the participants portfolio being able to generate an inflation-adjusted income
during retirement, or perhaps a combination of the above.
- Should the risk that is measured be a function of
the persons time horizon?
- Does the participant understand investments
sufficiently well to answer the questions intelligently? Are the questions worded in such
a fashion as to counter the participants biases? If the plan sponsor is concerned about
the participants knowledge of investing, should risk tolerance questionnaires even
be given?
- Should risk tolerance questionnaires be given out
before or after participants have gone through educational programs?
- Does a plan sponsor have an obligation to review
the allocations that participants are using? For example, a young participant can be
overly concerned over losing money and put her total portfolio in a stable asset fund.
Should a fiduciary advise her that her selection may be imprudent?
Arriving at the appropriate risk tolerance level
to input into the portfolio optimizer is a challenge. In fact, a persons risk
tolerance level might be so "soft and fuzzy" and fluid that quantifying it in a
universally acceptable fashion may not even be achievable. No plan sponsor or vendor
should use an assessment yardstick whose validity rests on extremely shaky ground.
If a plan sponsor or vendor feels that the issues
surrounding optimizerswhat they are and
are not, the accuracy of the inputs, and the
appropriateness of the outputare sufficiently well established so as to withstand
lawsuits from unhappy participants, then the next challenge is one
of communications. Personal data has to be
gathered from the participant, the risk tolerance questionnaire must be taken, input must
be processed, and then the recommended asset allocation has to be returned to the
participant, presumably with commentary to maximize the likelihood of implementation.
Since asset allocation services claim to be advice-driven, channels for ongoing
communication must be established.
Individuals, who on their own seek investment and
financial planning advice, meet regularly with their advisors. During these sessions, each
of which can easily last an hour or two, a strong interpersonal relationship can be
developed. The advisor, by watching the clients facial expressions and body
movements and listening to the clients questions and comments, can tell if the
client is comfortable with the recommendations and the reasons for them. Concerns can be
immediately addressed. The value of human interaction is readily appreciated.
Since one-on-one meetings have limited use in the
self-directed retirement plan market (too many participants, too few qualified advisors,
and too little time), vendors are recommending the Internet as the communications vehicle.
Why asset allocation vendors assume that workforces who do not using recordkeepers
Web sites will embrace theirs is not clear and may be just wishful thinking. After all,
the percent of 401(k) plan participants using their current vendors Web sites that
is bantered around at conferences is just 3-10%. Furthermore, most inquiries are only for
fund performances and to check account balances.
Even if participants are willing to use the
Internet, its effectiveness as a communications tool has yet to be determined. For
example, how do you communicate advice over the Internet? It is one thing to e-mail
documents, but it is something else to write the advice in language that the average
participant will understand. What happens if a participant does not understand the advice
or has questions? Will the participant have the writing skills and investment knowledge to
query the advisor? Even if she does, will she take the time to do it? The communication
problems become compounded if the risk assessment includes, as it probably will,
non-401(k) assets and needs, such as educating children.
Plan sponsors complain that participants do not
read the current short, attractive, and colorful materials they pass-out. Why, then, is it
realistic to expect most participants to read lengthy market reports, investment
commentaries, and pay attention to rebalancing notices or recommendations for asset
allocation changes when they appear on a Web site or arrive via e-mail?
Unless asset allocation vendors can make a
believable argument for using the Internet as the primary or sole channel of
communications, plan sponsors have little reason to believe that their participants will
be able to effectively use an asset allocation service. Using the Internet to look-up an
inn at which to stay on a ski vacation is quite different than using the Internet as the
means for high level communications. After all, how many participants are skilled at
writing English? Computer literacy cannot be equated with the ability to articulate
relatively unfamiliar and sophisticated concepts in written language.
The importance of asset allocation is not being
challenged. The issues that plan sponsors must face are simple:
- Should portfolio optimizers, with all their
limitations, be used for a purposeadvice generationfor which they were never
intended?
- Can risk tolerance questionnaires accurately
assess the risk profile of participants, and even if they do, how should the results
affect the choice of the portfolio used to fund retirement needs?
- Is it realistic to assume, based on current
participant behavior and literacy levels, that the Internet can be the primary channel of
communications and advice giving for the average participant in a self-directed retirement
plan?
- Is well-intentioned, but inappropriate, advice
better than no advice at all?
The answers to these questions will determine the
success or failure of asset allocation services.
1 1998 Retirement Confidence
Survey (Employee Benefit Research Institute).
2 Fifth Defined Contribution Plan Survey (John
Hancock Financial Services, 1997).
3 As quoted in "Five Investing Lessons from
Americas Top Pension Fund" by Jason Zweig. Money (Jan. 1998).
4 Paulos, John Allen. "Pick a Number, Any
Number." Worth (April 1995).
5 Koretz, Gene. "A D+ for Dismal
Scientists?" Business Week (Sept. 25, 1995).
6 Linden, Dana Weschler. "Dismal Days for the
Dismal Science." Forbes (April 22, 1996).
7 Sheridan, William. The Fortune Sellers
(John Wiley & Sons, 1998).
8 Statman, Meir. "Investor Sentiment."
Presented at the Using Behavioral Finance to Improve Investment Decisions
Conference (Association for Investment Management and Research, 1999). See also
"Bullish or Bearish?" Financial Analysts Journal (May/June 1998) by
Statman and Roger G. Clarke.
9 Keynes, John Maynard. "Economic Model
Construction and Econometrics." The Philosophy of Economics. Edited by Daniel
M. Housman. (Cambridge University Press, 1994).
10 Sheridan, William. The Fortune Sellers
(John Wiley & Sons, 1998).
11 Clements, Michael P. and Hendry, David F. Forecasting
Economic Time Series (Cambridge University Press, 1998).
12 Mean-variance optimization assumes that fund
returns are distributed evenly around the mean (a "normal" distribution). Figure
1 compares this assumption (the dotted curve) to the actual returns of a fund (the solid
curve). Notice how the actual distribution strays considerably from the assumption. For a
discussion of normal versus skewed distributions, see Chapter 1 in The Math Behind Wall
Street by Nicholas Teebagy (Four Walls Eight Windows 1998). Figure 1 is based on an
excerpt from The Streetlight Syndrome: Old and New Ways of Thinking About Risk
presented by Phil Fortuna of Scudder Kemper Investments at the Using Behavioral Finance
to Improve Investment Decisions Conference (Association for Investment
Management and Research, 1999). Used by permission.
13 Graham, Benjamin. The Intelligent Investor.
(Harper and Row, 1993).
14 Ibid.
15 De Bondt, Werner F. M. "What do Economists
Know About the Stock Market?" The Journal of Portfolio Management (Winter
1991).
16 Shiller, Robert. "Do Stock Prices Move Too
Much to be Justified by Subsequent Changes in Dividends?" American Economic Review.
(June 1993).
17 See "Rating Risk Questionnaires." Plan
Sponsor (Nov. 1998) by Tina Ruyter.
18 Tversky, Amos, and Daniel Kahneman. "The
Framing of Decisions and the Rationality of Choice." Science (January 30,
1981).
19 See "Chapter 7: The Psychology of Choice
and the Assumptions of Economics" in Quasi Rational Economics by Richard H.
Thaler (Russell Sage Foundation, 1991). |