© Edhec 2002
Desperately Seeking Pure Style Indexes
Lionel Martellini
Marshall School of Business
University of Southern California
Chercheur Associé EDHEC martelli@usc.edu
Joint work with Noël Amenc
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Outline
• Motivation
– Performance Mesurement and Asset Allocation
– Problems with Hedge Fund Indexes
• The World of Hedge Fund Indexes
– Overview of Popular Hedge Fund Strategies
– Survey of Existing Hedge Fund Indexes
• Hedge Fund Indexes are not Created Equal
– Heterogeity in Competing Hedge Fund Index Returns
– Implications for Asset Allocation
• Desperately Seeking Pure Style Indexes
– Statistical Approach
– Portfolio Approach
• How Pure is Pure?
– The Two Basic Theorems of Pure Indexing
– Testing Representativeness of Pure Indexes
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Motivation
From an Absolute to a Relative Return Perspective
• HF managers often use risk-free rate as a benchmark
• This absolute return approach is theoretically valid if and only if
– CAPM is the true model
– Hedge fund beta is zero
• Hedge fund indexes and sub-indexes are a natural choice for benchmarking hedge fund returns
• Right benchmarking is a fundamental problem in the presence of incentive fees
• Reliable HF indexes are also needed for
– Strategic Asset Allocation
– Tactical Asset Allocation
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Motivation
Equity Universe, Sub-Universes, and Specialized Indexes
Universe of Equity
(20000+)
MSCI Sub-Universe
Russell Sub Universe
Wilshire Sub-Universe (5000 approx)
S&P Indices (value, growth)
Russell Indices (growth,value)
• Composite of World Unknown
• Sub-universe (e.g., MSCI) may or may not represent World Index
• Competing indexes for the same universe
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Motivation
HF Universe, Sub-Universes, and Specialized Indexes
Zurich Hedge Fund Indices
Zurich Sub-Universe (1300 approx)
Universe of Hedge
Funds (6000+)
CSFB/Tremont Index
TASS Sub-Universe
HFR Sub Universe
EACM 100
• Composite of World Unknown
• Sub-universe (e.g., HFR, TASS) may or may not represent World Index
• Competing indexes for the same universe
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Motivation
Problems are Amplified for Hedge Fund Indexes
• Existing indexes are not fully representative
– Because of the lack of regulation on hedge fund performance disclosure, existing data bases only cover a relatively small fraction of the hedge fund population
– Probably only a little more than half of existing hedge funds choose to selfreport their performance to one of the major hedge fund databases
– One of the most popular hedge fund indexes, the EACM 100, does not account for more than a tiny percentage of all existing hedge funds
– Most HF indexes are equally-weighted (all but CSFB/Tremont)
• Existing indexes are biased
– Most hedge fund indexes are based upon managers' self-proclaimed styles
– Given that hedge fund managers jealously protect the secret of their investment strategies (the so-called black-box problem), relying on managers' self-proclaimed style is actually almost a necessity
– This procedure only makes sense under the following two conditions: (1) a manager follows a unique investment and (2) a manager's self-proclaimed style matches the manager's actual trading strategies
– Style drift problem (see for example Lhabitant (2001))
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Motivation
Pure Style Indexes are not Observable
Population of hedge funds following a given strategy
Lack of representativeness
Sample of hedge funds in the database used by a given commercial index
© Edhec 2002
Presence of a style bias
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
World of HF Indexes – Popular Strategies
Hedge Funds Classification
Hedge Fund Classifications
© Edhec 2002
Relative Value
Bond Hedge Equity Market Neutral
Convertible Arbitrage
Event Driven
Deal Arbitrage
Distressed Debt
Bankruptcy
Multi-Strategy
Equity Hedge
Long/Short Equity Long Bias
Global Macro
Discretionary Systematic
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
World of HF Indexes – Popular Strategies
Hedge Funds Styles
• Directional strategies: aimed at benefiting from market movements and trends
– Global macro
– Hedge (long bias)
– Long (e.g. “growth” or “value” stocks)
– Short (e.g. “overvalued”, “glamour” stocks)
• Non directional strategies:
– Event driven (corporate events such as takeovers, spin-offs, mergers, etc.)
– Restructuring (buying or shorting securities of companies under Chapter 11 and/or undergoing some form of reorganization)
– Fixed-income arbitrage (long and short via treasuries, corporate and/or asset-backed securities)
– Capital structure arbitrage (buying and selling different securities of the same issuer, e.g., convertibles/common stock)
– Equity market neutral (long-short zero beta strategies)
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
World of HF Indexes – Competing Providers
There exist at least a Dozen HF Index Providers
Providers
EACM
HFR
CSFB/Tremont
Zurich Capital
Van Hedge
Hennessee Group
Hedgefund.net
LJH Global Investments
MAR
Altvest
Magnum
# of Indexes Launch Date # of Funds
13
15
9
1996
1994
1999
100
1,100
340
Website eacmalternative.com
hfr.com
hedgeindex.com
5
12
22
33
16
15
13
8
2001
1995
1992
1979
1992
1990
2000
1994
60
750
450
1,800
800
1,300
1,400
NA zcmgroup.com
vanhedge.com
hedgefnd.com
hedgefund.net
ljh.com
marhedge.com
altvest.com
magnum.com
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
World of HF Indexes – Competing Providers
Strategies Covered in this Paper
Sub-Universe
Convertible Arbitrage
Emerging Markets
Equity Market Neutral
Event Driven
Fixed Income Arbitrage
Global Macro
Long/Short
Merger Arbitrage
Relative Value
Short Selling
Distressed Securities
Fund of Funds
List of Competing Indexes
CSFB, HFR, EACM, Zurich, Hennessee, HF Net
CSFB, Altvest, HFR, MAR, Van Hedge, Hennessee, HF Net
CSFB, Van Hedge, HFR, MAR, Hennessee, HF Net
CSFB, Altvest, MAR, EACM, HFR, Hennessee, HF Net, Zurich
CSFB, HFR, Van Hedge, Hennessee, HF Net
CSFB, Altvest, Van Hedge, MAR, HFR, Hennessee, HF Net, Magnum 02/97
CSFB, Altvest, Zurich, EACM, HF Net 01/98
Altvest, HFR, Zurich, Hennessee, EACM, HF Net 01/98
Altvest, HFR, Van Hedge, EACM, HF Net
Altvest, HFR, Van Hedge, MAR, EACM
Van Hedge, Altvest, HFR, EACM, Zurich, HF Net, Hennessee
Van Hedge, Altvest, HFR, Zurich
01/96
01/96
01/98
01/98
Date
01/98
01/96
01/96
01/98
01/96
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
World of HF Indexes – Competing Providers
Strategies Not Covered in this Paper
© Edhec 2002
Sub-Universe
Market Timing
Aggressive Growth
International
Special Situations
Opportunity
List of Competing indexes
HFR, Van Hedge
Magnum, Van Hedge, HF Net
Magnum, MAR, EACM, Hennessee
Magnum, Van Hedge, HF Net
Magnum, Van Hedge, EACM, HF Net
Emerging Markets - Latin America
Fixed Income - High Yield
Regulation D
Sectors - Energy
Sectors - Financial
HFR, Hennessee
HFR, Hennessee
HFR, HF Net
HFR, HF Net
Van Hedge, Altvest, HFR, EACM, Zurich, HF Net
Sectors - Technology
Sectors - Health Care
Statistical Arbitrage
Capital growth
Altvest, HFR, Magnum, HF Net
Altvest, HFR, HF Net, Hennessee
HFR, HF Net
Magnum, Hennessee
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Hedge Fund Indexes are not Created Equal
Heterogenity in Hedge Fund Indexes – Max Difference
Sub-Universe
Convertible Arbitrage
Emerging Markets
Max Difference (with dates and indexes)
4.75% (Oct 98; CSFB (-4.67) / Hennessee (0.08))
19.45% (Aug 98; (MARH -26.65) / Altvest (-7.2))
Equity Market Neutral 5.00% (Dec 99; Hennessee (0.2) / Van Hedge (5.2))
Event Driven 5.06% (Aug 98; CSFB (-11.77%) / Altvest (-6.71))
Fixed Income Arbitrage 10.98% (Oct 98; HF Net (-10.78) / Van Hedge (0.2))
Global Macro
Long/Short
Merger Arbitrage
17.80% (May 00: Van Hedge (-5.80) / HF Net (12))
22.04% (Feb 00: EACM (-1.56) / Zurich (20.48))
1.85% (Sep 98: Altvest (-0.11) / HFR (1.74))
Relative Value
Short Selling
10.47% (Sep 98: EACM (-6.07) / Van Hedge (4.40))
21.20% (Feb 00: Van Hedge (-24.3) / EACM (-3.09))
Distressed Securities 7.38% (Aug 98: HF Net (-12.08) / Van Hedge (-4.70))
Fund of Funds 8.01% (Dec 99: MAR-Zurich (2.41) / Altvest (10.42))
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Hedge Fund Indexes are not Created Equal
Heterogeity in Hedge Fund Indexes – Correlation
Sub-Universe
Convertible Arbitrage
Emerging Markets
Equity Market Neutral
Event Driven
Fixed Income Arbitrage
Global Macro
Long/Short
Merger Arbitrage
Relative Value
Short Selling
Distressed Securities
Fund of Funds
Average Correlation Lowest Correlation
0.8183
0.6350
0.9284
0.4276
0.9232
0.8301
0.1258
0.8458
0.5407
0.5598
0.4575
0.9193
0.6752
0.8811
0.8645
0.8757
0.2254
0.2698
-0.1901
0.8797
0.3042
0.7796
0.7218
0.7985
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Hedge Fund Indexes are not Created Equal
Implications for Asset Allocation
14.00%
12.00%
10.00%
8.00%
100% S&P 500
6.00%
4.00%
2.00%
0.00%
0.00% 2.00%
100% Lehm an US aggregate
4.00% 6.00%
CSFB HFR
8.00%
Van Hedge
10.00%
Henessee HF net
12.00% 14.00%
S&P + Lehman
16.00% 18.00%
Efficient frontiers based on monthly data for the period extending from January 1996 to October 2001
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Investment in Hedge Funds
• Problems
– Competing indexes disagree
– All are potentially flawed
• Can not tell which is best
– All existing indexes have both advantages and drawbacks
– For example, Zurich indexes may be less biased than some of their competitors, but they are less representative
• Statistical approach
• Portfolio approach
– Maximization of Representativeness
– Minimization of Bias
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Statistical Approach – Kalman Filter
• Simple model
R kt
I t
e kt
– R
–
I t
– e kt kt is the return on competing index k is the (unobservable) return on pure index is the noise, measurement error resulting from presence of biases and absence of representativeness
• Assume normally distributed pure indexes and measurement errors
• Kalman filter is used both to evaluate the likelihood function and to forecast and smooth the unobserved state variables
• Here, our motivation is to estimate (smooth) the unobserved pure index, based on the observed returns on competing indexes:
I
ˆ t , T
:
E
I t
R
1
, R
2
,..., R
T
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Statistical Approach – The Results
Sub-Universe Mean Volatility Est. Error Average Correlation
Conv. Arbitrage 0.85% (0.94%) 1.17% (1.34%) 0.28% 0.9068
Emerging Markets 0.08% (0.43%) 5.16% (5.34%) 0.04%
Eq. Market Neutr.
0.91% (0.83%) 0.40% (1.03%) 0.17%
0.9472
0.6632
Event Driven 0.93% (0.86%) 1.94% (2.09%) 0.22%
Fixed Income Arb. 0.56% (0.36%) 1.36% (1.70%) 0.04%
Global Macro 0.92% (0.69%) 2.34% (2.55%) 0.34%
Long/Short 1.13% (1.11%) 1.11% (3.13%) 0.00%
0.9641
0.7260
0.8157
0.6407
Merger Arb.
1.11% (0.89%) 1.19% (1.31%) 0.15%
Relative Value 1.01% (0.90%) 0.91% (1.97%) 0.14%
Short Selling
Distressed
0.16% (0.49%) 7.45% (7.70%)
0.52% (0.73%) 2.21% (2.26%)
1.07%
0.27%
Fund of Funds 0.73% (0.91%) 2.51% (2.52%) 0.26%
0.9649
0.8201
0.9277
0.9353
0.9398
Performance of Kalman filter pure index (in parenthesis, the average of competing index)
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Statistical Approach – Convertible Arbitrage
0.1
0.08
0.06
0.04
0.02
0
Fe b-
98
Ap r-9
8
Ju n-9
8
Au g-
98
Oc t-9
8
De c-9
8
Fe b-
99
Ap r-9
9
Ju n-9
9
Au g-
99
Oc t-9
9
De c-9
9
Fe b-
00
Ap r-0
0
Ju n-0
0
Au g-
00
Oc t-0
0
De c-0
0
-0.02
-0.04
-0.06
-0.08
-0.1
© Edhec 2002
Zurich
EACM
CSFB
Kalman
Henessee
Kalman - 2 Sigmas
Mesure de la Performance et des Risques de la Gestion Alternative
HFR
Kalman + 2 Sigmas
18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – The Method
• Black-Box problem
– A pure index generated Kalman filtering techniques has an appealing built-in element of optimality (minimized mean squared error)
– It can not, however, be regarded as index in its own right, since it can not be expressed as a portfolio of individual hedge funds
• Portfolio approach
– Taking a portfolio of existing indexes should intuitively be better than selecting any of them
– Is equally-weighting a good scheme?
• Maximization of representativeness
– Principal component analysis
• Minimization of bias
– Minimum-variance analysis
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – PCA
• Use factor analysis techniques to generate a set of pure indexes
– They can be thought of as the best possible one-dimensional summaries of information conveyed by competing indexes for a given style, in the sense of the larger fraction of the variance explained.
– Here, we are looking for the portfolio weights that make the combination of competing indexes capture the largest possible fraction of the information contained in the data from the various competing indexes
• The method
– From a mathematical standpoint, it involves transforming a set of K correlated competing indexes into a set of orthogonal variables, or implicit factors, which reproduces the original information present in the correlation structure
– Each implicit factor is defined as a linear combination of original variables
– Use the first component of a PCA of competing indexes as a candidate for a pure style index (typically captures a large proportion of cross-sectional variations because competing styles tend to be at least somewhat positively correlated)
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
PCA – The Results
© Edhec 2002
Sub-Universe
Convertible Arbitrage
Emerging Markets
Equity Market Neutral
Event Driven
Fixed Income Arbitrage
Global Macro
Long/Short
Merger Arbitrage
# of Indexes % of Variance Explained
6 84.91
7
6
91.97
58.91
8
6
8
5
4
85.41
65
74.13
86.8
83.81
Relative Value
Short Selling
Distressed Securities
Fund of Funds
7
5
5
5
71.26
78.42
77.6
91.19
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – Min Var Analysis
• Pure hedge fund indexes generated as the first component in a factor analysis should be as representative as possible since there is no other linear combination of competing indexes that implies a lower information loss
• Another approach consists in focusing on minimization of the bias
• Use same model as before
R kt
I t
e kt
• Add assumptions
– Noise term is zero on average
– Noise term is uncorrelated with return on pure index
– Homoscedastic model
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – Min Var Analysis
• Define the return on a portfolio of indexes
R pt
w '
R t
I t
w '
e t
• Under previous assumptions, we have that
E
Var pt
pt
E
t
I
2 w '
e
w
• The problem of minimizing the bias is
Min w
Var
pt
w '
e
s .
t .
w '
1
1 w
• Solution is w
*
1 '
1 ee
1 ee
1
1
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – Additional Assumption
• If one is willing to make the additional assumption of no correlation between noise terms for various competing indexes, then the variance-covariance matrix of residuals is diagonal, and one obtains the following simple solution w i
* j
i
2
j
2
1
I
2
1
I
2
• May also impose positivity constraints to ensure that resulting index is a long-only portfolio of individual hedge funds
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Desperately Seeking Pure Style Indexes
Portfolio Approach – Additional Assumption
© Edhec 2002
Sub-Universe Mean Volatility
Convertible Arbitrage 1.08% (0.94%) 1.13% (1.34%)
Average Correlation
0.90
Emerging Markets 0.80% (0.43%) 3.33% (5.34%)
Equity Market Neutral 0.85% (0.83%) 0.44% (1.03%)
0.95
0.58
Event Driven 0.95% (0.86%) 3.78% (2.09%)
Fixed Income Arbitrage 0.37% (0.36%) 1.33% (1.70%)
Global Macro
Long/Short
0.09% (0.69%) 3.73% (2.55%)
0.78% (1.11%) 0.76% (3.13%)
0.87
0.78
0.70
0.56
Merger Arb.
Relative Value
Short Selling
Distressed
Fund of Funds
0.99% (0.89%) 1.15% (1.31%)
0.82% (0.90%) 1.00% (1.97%)
0.82% (0.49%) 6.95% (7.70%)
0.46% (0.73%) 2.55% (2.26%)
0.94% (0.91%) 2.45% (2.52%)
0.92
0.68
0.47
0.80
0.95
Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
How Pure is Pure?
The Two (Obvious) Theorems of Pure Indexing
• PCA and min-var analysis have appealing element of optimality
• However, any portfolio (e.g., equally-weighted portfolio) should perform better than competing indexes
• Theorem 1: An index of the indexes is always less biased than the average of the set of indexes it is extracted from
e
2 p
j n
1 w j
e
2 j
• Theorem 2: An index of the indexes is always more representative than any competing index I
1
I
2
I
3
I
3
I
1
I
2
Index 1
I
1
I
2
I
3
I
2
I
1
I
3
Index 2
18/06/02 © Edhec 2002
Index 3
Mesure de la Performance et des Risques de la Gestion Alternative
How Pure is Pure?
Testing Representativeness – The Method
• Reduction of bias is very hard to test (chicken-and-egg problem)
• We have tested enhancement of representativeness using the following test experiment
– We have merged the 3 major databases providing information on individual fund return (MAR, TASS and HFR)
– We have also added data on funds which do not report to any data base, that had been directly obtained from administrators
– We have gathered monthly returns on a total of 7,422 hedge funds, including 2,317 funds that do not report their returns to the major data bases
– We have formed equally-weighted portfolios for each style based on managers’ self-proclaimed styles and compute correlation with pure indexes
• These portfolios are
– Arguably biased
– Undoubtly representative
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
How Pure is Pure?
Testing Representativeness – The Results
Sub-Universe Kalman (%) PCA (%) Min. Bias (%) Min. Bias Positive Weights
Convertible Arbitrage 0.84 (67%) 0.84 (67%) 0.76 (33%)
Emerging Markets 0.95 (29%) 0.98 (86%) 0.95 (29%)
0.78 (50%)
0.86 (14%)
Equity Market Neutral 0.38 (83%) 0.41 (83%) 0.38 (67%)
Event Driven 0.95 (75%) 0.96 (100%) 0.92 (37%)
Fixed Income Arbitrage 0.93 (80%) 0.81 (60%) 0.88 (60%)
Global Macro 0.71 (86%) 0.77 (86%) 0.55 (43%)
0.38 (67%)
0.92 (37%)
0.76 (60%)
0.78 (86%)
Long/Short
Merger Arbitrage
Relative Value
Short Selling
Distressed
Fund of Funds
0.63 (40%)
0.85 (67%)
0.88 (83%)
0.69 (50%)
0.95 (100%)
0.93 (75%)
0.98 (100%)
0.86 (67%)
0.89 (83%)
0.73 (50%)
0.94 (86%)
0.94 (100%)
0.41 (20%)
0.86 (67%)
0.61 (17%)
0.44 (0%)
0.82 (14%)
0.93 (75%)
0.24 (20%)
0.84 (67%)
0.88 (83%)
0.75 (100%)
0.91 (43%)
0.83 (25%)
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02
Conclusion
• Contribution
– Document heterogeneity in competing hedge fund index providers
– Attempt to provide remedies to the problem
• Extensions
– We have suggested that a database of pure style indexes be maintained at the EDHEC-MISYS Risk and Asset Management
Research Center, and posted on a dedicated web site
– The index construction methodology
• Step 1: Use the first 3 years of monthly returns to calibrate the model.
• Step 2: Perform a PCA analysis of competing indexes for each strategy on the data used for calibration purposes
• Step 3: These portfolios are held for 3 months, their monthly returns are recorded, and the same process is repeated
– Our results can easily be extended to traditional investment styles such as growth/value, small-cap/large-cap
© Edhec 2002 Mesure de la Performance et des Risques de la Gestion Alternative 18/06/02