| Overview
of "The Small-Cap-Alpha Myth"
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By Melissa Johnson September 1,
2001 |
Many people are led to believe that active managers can provide
a greater advantage and higher value to investors in the small-cap
versus large-cap market, thus resulting in a larger alpha. A large
alpha infers that the stock or mutual fund has performed better
than would be expected based on its volatility or risk, suggesting
that active management is the reason for the better than expected
performance.
Richard M. Ennis and Michael D. Sebastian constructed a sample
of 128 products from the Mobius Group M-Search database, a small-cap
database of institutional commingled funds and composites of separate
accounts. They concluded that this so-called small-cap-alpha advantage
is actually the "small-cap-alpha myth." At first view,
it appears that a small-cap alpha advantage does exist. When looking
at the ten-year period ending June 30, 2001, their research showed
that the median portfolio in their sample outperformed the Russell
2000 Index by 4.04%. But a more accurate picture formed when they
delved deeper.
When three important performance evaluation methods were considered,
the alpha diminished to virtually zero. These performance evaluation
errors include 1) neglecting to account for management fees, 2)
comparing the portfolio to an inappropriate benchmark, and 3)
overlooking survivorship bias.
Error #1
Ninety percent of the products in the sample reported performance
gross of fees. When fees were included in the equation, the net
alpha dropped from 4.04% to 3.09%.
Error #2
To derive an accurate net return, appropriate benchmarks must
be used for comparison. A single index, such as the Russell 2000,
cannot be used for proper comparison if the portfolios being compared
are not exactly the same in style and make-up as that index. Ennis
and Sebastian created effective style mixes (ESMs) for the products
being studied. Based on a type of multiple regression, ESMs are
a more precise way to benchmark. Now accounting for errors #1
and #2, the net alpha dropped from 4.04% to 1.2%.
Error #3
Many databases do not include the records of products that no
longer survive, which hyperinflates the performance reports of
active managers and funds. This is called Survivorship Bias and
does not accurately reflect true performance.
When considering all three performance evaluation errors, Ennis
and Sebastian concluded that the true median alpha in their sample
is "likely to be zero or negative, not 4%." They summarized
that there is "no support for the claim that active management
of small-cap portfolios is any more fruitful than it is for large-cap
portfolios." In other words, forget about it! Focus on the
only important question of investing: "what asset allocation
of index funds is most appropriate for you?"
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Source: "The
Small-Cap-Alpha Myth", Richard M. Ennis, CFA; Michael
D. Sebastian, Ennis Knupp + Associates, September 2001 (www.ennisknupp.com).
Richard M. Ennis, CFA, is founder, principal, and consultant
for Ennis, Knupp & Associates. Prior to joining Ennis,
Knupp & Associates, he was affiliated with A.G. Becker,
O'Brien (now Wilshire) Associates and Transamerica Investment
Management. Mr. Ennis is the author of numerous articles,
coauthor of Spending Policy for Educational Endowments, and
a recipient of a Financial Analysts Journal Graham and Dodd
award. Mr. Ennis holds a B.S. from California State University
at Northridge and an M.B.A. from the University of California
at Los Angeles. |