Attackoftheclones
Attackoftheclones
  of
                the                        Clones
                 Hedge funds are considered by many investors to be an attractive investment, thanks in
                 large part to their diversification benefits and distinctive risk profiles. The major drawbacks
                 are their high fees and lack of transparency. Research by Jasmina Hasanhodzic and Andrew
                 W. Lo of the Massachusetts Institute of Technology raises the possibility of creating passive
                 portfolios that provide similar risk exposures to those of hedge funds at lower costs and with
                 greater transparency. Hasanhodzic and Lo find that for certain hedge fund strategies, these
                 hedge fund “clones” perform well enough to warrant serious consideration.
                 A
                                s institutional investors take a more active in-   Plan sponsors require a certain degree of liquidity in their
                                  terest in alternative investments, a signifi-     assets to meet their pension obligations and also desire sig-
                                   cant gap has emerged between the culture        nificant capacity because of their limited resources in man-
                                     and expectations of those investors and       aging large pools of assets; hedge fund managers routinely
                                      hedge fund managers. Pension plan            impose lockups of one to three years, and the most success-
                 sponsors typically require transparency from their managers       ful managers have the least capacity to offer, in many cases
                 and impose numerous restrictions on their investment man-         returning investor capital once they make their personal for-
                 dates because of regulatory requirements such as ERISA            tunes. And as fiduciaries, plan sponsors are hypersensitive to
                 rules; hedge fund managers rarely provide position-level          the outsize fees that hedge funds charge and are concerned
                 transparency and bristle at any restrictions on their invest-     about misaligned incentives induced by performance fees;
                 ment process, saying that restrictions can hurt performance.      hedge fund managers argue that their fees are fair compen-
00 • INSTITUTIONAL INVESTOR’S ALPHA • JUNE 2006                                                     Illustrations by Edel Rodriguez for Alpha
Hasanhodzic and Lo
                 sation for their unique investment acumen — and at least suggests that for certain classes of hedge fund strategies,
                 for now, the market seems to agree.                                        portable beta may be an even more important source of
                     This cultural gap raises the natural question of untapped expected returns and diversification.
                 whether it is possible to obtain hedge-fund-like returns
                 without investing in hedge funds. In other words, can BEFORE TURNING TO OUR empirical analysis, we
                 hedge fund returns be cloned?                                              provide two concrete examples that span the extremes of
                     In a series of recent papers, Harry Kat and Helder Palaro the hedge fund replication problem. For one hedge fund
                 of the Cass Business School at City University in London strategy, we show that replication can be accomplished
                 show that sophisticated dy-                                                                                  easily; for another strategy
                 namic trading strategies in-                                                                                 we find replication to be
                 volving liquid futures
                                                    Table 1: Capital Decimation Partners* almost                                        impossible using
                 contracts can replicate many         The monthly returns of fictitious Capital Decimation Partners’ simulated linear models.
                 of the statistical properties of     short-put-option strategy handily beat the Standard & Poor’s 500 index.     The first example is a
                 hedge fund returns. In fact,                                                 Standard &           Capital    hypothetical    strategy we
                 in a 2001 paper with Dim-                                                     Poor’s 500       Decimation    proposed several years ago
                                                      Statistic                                  index           Partners*
                 itris Bertsimas and Leonid                                                                                   called “Capital Decimation
                 Kogan of the Massachusetts           Monthly mean                                1.4%               3.6%     Partners,” or CDP, which
                 Institute of Technology, we          Monthly standard deviation                  3.6%               5.8%     yields an enviable track
                 show that the risk/return            Minimum month                             –8.9%               –18.3%    record that many investors
                 characteristics of securities        Maximum month                              14.0%               27.0%    would associate with a suc-
                 with very general payoff             Annual Sharpe ratio                         0.98                1.90    cessful hedge fund: a 43.1
                 functions (like hedge funds          Number of negative months                    36                  6      percent annualized mean
                 or complex derivatives) can          Correlation to S&P 500 index               100%                 61%     return and 20.0 percent an-
                 be synthetically replicated to       Growth of $1 since inception                 $4                 $26     nualized volatility, implying
                 an arbitrary degree of accu-         * January 1992 through December 1999.                Source: Lo (2001). a Sharpe ratio of 1.90, and
                 racy by dynamic trading                                                                                      with only six negative
                 strategies — called epsilon-arbitrage strategies — involving months over the 96-month simulation period from January
                 more liquid instruments. Although these results are encour- 1992 through December 1999 (see Table 1).
                 aging for the hedge fund replication problem, the strategies                   So what is CDP’s secret? The investment strategy in-
                 are quite complex and not easily implemented by the typi- volves shorting out-of-the-money S&P 500 put options
                 cal institutional investor.                                                on each monthly expiration date for maturities less than
                     In this article we take a slightly different tack: We con- or equal to three months, and with strikes approximately
                 struct “linear clones” — buy-and-hold portfolios of com- 7 percent out of the money.
                 mon risk factors like the Standard & Poor’s 500 and U.S.                       The essence of this strategy is the provision of insur-
                 dollar indexes, with portfolio weights estimated by a lin- ance. CDP investors receive option premiums for each op-
                 ear regression of a fund’s historical returns on market fac- tion contract sold short, and as long as the option contracts
                 tors — of a large number of individual hedge funds in the expire out of the money, no payments are necessary. From
                 TASS Hedge Fund Database. We then compare their this perspective the handsome returns to CDP investors
                 characteristics to those of the corresponding funds from seem more justifiable: In exchange for providing downside
                 which the clones are derived.                                              protection, CDP investors are paid a risk premium in the
                     If a hedge fund generates part of its expected return same way that insurance companies receive regular pay-
                 and risk profile from certain common risk factors, it may ments for providing earthquake or hurricane insurance.
                 be possible to design a low-cost, buy-and-hold portfolio                       Given the relatively infrequent nature of 7 percent
                 — not an active, dynamic trading strategy — that cap- losses, CDP’s risk/reward profile can seem very attractive
                 tures some of that fund’s risk/reward characteristics by in comparison to more traditional investments, but there
                 taking on just those risk exposures. For example, if a par- is nothing unusual or unique about CDP. Investors will-
                 ticular long-short equity hedge fund is 40 percent long ing to take on “tail risk” — the risk of rare but severe
                 growth stocks, it may be possible to create a passive port- events — will be paid well for this service (consider how
                 folio that has similar characteristics through a long-only much individuals are willing to pay each month for their
                 position in a passive growth portfolio coupled with a 60 homeowner’s, auto, health and life insurance policies).
                 percent short position in stock index futures.                             CDP involves few proprietary elements and can easily be
                     The magnitude of hedge fund alpha that can be cap- implemented by most investors; it is one example of a
                 tured by a linear clone depends, of course, on how much hedge-fund-like strategy that can readily be cloned.
                 of a fund’s expected return is driven by common risk fac-                      Now for the bad news. Consider the case of “Capital
                 tors versus manager-specific alpha. This can be measured Multiplication Partners,” or CMP, a hypothetical fund
                 empirically. Although portable-alpha strategies have be- based on a dynamic asset-allocation strategy between the
                 come fashionable lately among institutions, our research S&P 500 and one-month U.S. Treasury bills, where the
fund manager can correctly forecast which of the two ve-          which we have complete data for all of our factors (the TASS
hicles will do better in each month and invests the fund’s        database goes back to 1977). Of these funds, we drop those
assets in the higher-yielding instrument at the start of the      that do not report net-of-fee returns, those that report re-
month. (This example was first proposed by Robert Mer-             turns in currencies other than the U.S. dollar, those that re-
ton in his 15.415 Finance Theory class at the MIT Sloan           port returns less frequently than monthly, those that do not
School of Management in the 1970s.) The monthly re-               provide assets under management or provide only estimates
turn of this perfect-market-timing strategy is simply the         and those that have fewer than 36 monthly returns. These
larger of the monthly returns of the S&P 500 and T-bills.         filters yield a final sample of 1,610 funds.
    The source of alpha is clear. Merton observes that this           For each fund we estimate a linear regression of its
strategy is equivalent to a long-only investment in the           monthly historical returns on the following six risk factors:
S&P 500 plus a put option on the S&P 500 with a strike            the U.S. dollar index return, the return on the Lehman
price equal to the T-bill return. The economic value of           Brothers corporate AA intermediate bond index, the spread
this perfect market-timing is equal to the sum of monthly         between the Lehman BAA corporate bond index and the
put-option premiums over the life of the strategy.                Lehman Treasury index, the S&P 500 total return, the
    There is little doubt that such a strategy contains signifi-   Goldman Sachs commodity index return and the first-dif-
cant alpha indeed: A $1 investment in CMP in January              ference of the end-of-month value of the VIX Chicago
1926 would have grown to more than $23 billion by the             Board Options Exchange volatility index. (Throughout this
end of December 2004! Table 2 provides a more detailed            article all statistics, except for those related to the first-order
performance summary of CMP, whose Sharpe ratio exceeds            autocorrelation, have been annualized to facilitate interpre-
that of Warren Buffett’s Berkshire Hathaway, arguably the         tation and comparison.)
most successful pooled investment vehicle of all time.                We choose these six risk factors for two reasons: They
    It should be obvious to even the most naive investor          provide a reasonably broad cross-section of risk exposures
that CMP is a fantasy because no one can time the market          for the typical hedge fund (stocks, bonds, currencies, com-
perfectly. Therefore, attempting to replicate such a strate-      modities, credit and volatility), and each of the factor re-
gy with exchange-traded instruments seems hopeless. But           turns can be realized through relatively liquid instruments
suppose we try anyway. How close can we come? In par-
ticular, suppose we attempt to relate CMP’s monthly re-
turns to the monthly returns of the S&P 500 by fitting a
                                                                          Table 2: Capital Multiplication Partners*
straight line through a graph of their paired monthly re-           Based on a series of simulated monthly returns going back to 1926, the aptly named
turns, that is, a linear regression. The option-like nature of      Capital Multiplication Partners’ perfect-market-timing strategy easily beats its clone’s.
CMP’s perfect-market-timing strategy, which is inherently                                                   Standard &                Capital
nonlinear, cannot be captured by a straight line. However,                                                  Poor’s 500   Treasury   Multiplication
the formal statistical measure of how well the linear regres-       Statistic                                  index       bills      Partners            Clone
sion fits the data — the R2, a number between 0 and 100              Monthly mean                               1.0%        0.3%          2.6%              0.7%
percent that implies a perfect linear relationship at 100           Monthly standard deviation                 5.5%        0.3%          3.6%              3.0%
percent and no relationship at all at 0 — is 70.3 percent in        Minimum month                            –29.7%       –0.1%         –0.1%             –16.3%
this case, which suggests a very strong linear relationship         Maximum month                             42.6%        1.4%         42.6%             23.4%
indeed. But when the estimated linear regression is used to         Annual Sharpe ratio                        0.63        4.12          2.50               0.79
construct a buy-and-hold portfolio of the S&P 500 and               Number of negative months                   360         12            10                340
one-month T-bills, the results are not nearly as impressive         Correlation to S&P 500 index              100%         –2%           84%               100%
as CMP’s returns, as Table 2 shows.                                 Growth of $1 since inception             $3,098         $18       $2.3 x 1010          $429
    This example underscores the difficulty of replicating          * January 1926 through December 2004.                           Source: Authors’ calculations.
certain strategies that have genuine alpha with linear clones,
and it cautions against using the R2 as the only metric of        so that the returns of linear clones may be achievable in
success. Despite the high R2 achieved by the linear regres-       practice. In particular, there are forward contracts for each
sion of CMP’s returns on the market index, the actual per-        of the component currencies of the U.S. dollar index and
formance of the linear clone falls far short of the strategy      futures contracts for the stock and bond indexes and for the
because a linear model will never be able to capture the          components of the commodity index. Futures contracts on
option-like payoff structure of the perfect market-timer.         the VIX index were introduced by the CBOE in March
                                                                  2004 and are not as liquid as the other index futures, but
TO EXPLORE THE FULL RANGE of possibilities for                    the over-the-counter market for variance and volatility
replicating hedge fund returns illustrated by the two extremes    swaps is quite well developed.
of CDP and CMP, we investigate the performance of linear              The linear-regression model provides a simple but use-
clones for a sample of individual hedge funds drawn from          ful decomposition of a hedge fund’s expected return into
the TASS Hedge Fund Live Database over the sample period          two distinct components — beta coefficients multiplied
from February 1986 through September 2005. We start our           by the risk premiums associated with various risk factors,
analysis in February 1986 because this is the earliest date for   and manager-specific alpha. The intuition for this decom-
                position is straightforward. Hedge funds generate their ex-     spread (27.1 percent), and the average contribution of
                pected returns by taking on certain generic risks for which     manager-specific alpha is –33.3 percent.
                they are compensated, like market or credit risk, and also          This implies that convertible-arbitrage funds, on aver-
                by taking advantage of insights and opportunities that are      age, earn more than all of their mean returns from the risk
                specific to the manager.                                         premiums associated with the six factor exposures, and that
                    By “manager-specific alpha,” we do not mean to imply         the average contribution of other sources of alpha is nega-
                that a hedge fund’s unique source of alpha is without risk.     tive. Of course, this does not mean that convertible-arbitrage
                We are simply distinguishing this source of expected return     managers are not adding value. The results are averages
                                           from those that have clearly iden-   across all funds in the sample; hence, the positive manager-
                                           tifiable risk factors associated     specific alphas of successful managers will be dampened and,
  “For certain types                       with them. In particular, it may     in some cases, outweighed by the negative manager-specific
                                           well be the case that manager-       alphas of the unsuccessful ones. Moreover, all of the statistics
    of hedge fund                          specific alpha arises from factors    reported in our study are estimates only and therefore sub-
                                           other than the six we have pro-      ject to a certain amount of estimation error.
     strategies, a                         posed, and a more refined list of         In contrast to the convertible-arbitrage funds, for the
                                           factors — one that reflects the      ten funds in the dedicated short-bias category, manager-
  passive buy-and-                         particular investment style of the   specific alpha accounts for 225.6 percent of the total mean
                                           manager — may yield a better-        return, while the contribution of the S&P 500 factor is
    hold approach                          performing linear clone.             negative. This result is not as anomalous as it may seem.
                                               A similar decomposition for      The bull market of the 1990s implies a performance drag
  may yield some of                        a hedge fund’s return variance       for any fund with negative exposure to the S&P 500.
                                           can be derived that is the sum of    Thus, dedicated short-bias managers that have generated
  the same benefits                         three distinct components: the       positive performance during this period must have done
                                           variances of the risk factors mul-   so through other means.
   as hedge funds.”                        tiplied by the squared beta coef-        A concrete illustration of this intuition is given by the
                                           ficients, the variance of the        decomposition of the annualized average return of the
        — JASMINA HASANHODZIC
                                           fund-specific sources of ran-        two most successful funds in the dedicated short-bias cat-
             AND ANDREW W. LO
                                           domness or “residual” (which         egory. From 1997 through 2005 these two funds posted
                                           may be related to the specific       annualized net-of-fee returns of 15.56 percent and 10.02
                economic sources of alpha) and the weighted covariances         percent, respectively, but the contribution of the S&P
                among the factors. This decomposition highlights the fact       500 factor to these annualized returns was negative in
                that a hedge fund can have several sources of risk, each of     both cases. In fact, the six factors account for very little of
                which should yield some risk premium — that is, risk-           the two funds’ performance; hence, the manager-specific
                based alpha — otherwise, investors would not be willing         alphas are particularly significant for these two funds.
                to bear such risk. By taking on exposure to multiple risk           Between the two extremes of convertible-arbitrage and
                factors, a hedge fund can generate attractive expected re-      dedicated short-bias funds, there is considerable variation
                turns from the investor’s perspective, as we saw with Capi-     in the importance of manager-specific alpha for the other
                tal Decimation Partners.                                        strategy categories. For the entire sample of 1,610 funds,
                    Using the linear-regression model to decompose a            61.0 percent of the average total return is attributable to
                fund’s expected returns, we can now reformulate the ques-       manager-specific alpha, implying that, on average, the re-
                tion of whether a hedge fund strategy can be cloned by          maining 39.0 percent is due to the risk premiums from
                asking how much of a hedge fund’s alpha is due to risk          our six factors. These results suggest that for certain types
                premiums from identifiable factors. If it is a significant      of hedge fund strategies, a passive buy-and-hold approach
                portion, then a passive portfolio with just those risk expo-    may yield some of the same benefits as hedge funds, but
                sures — created by means of liquid instruments such as          in a transparent, scalable and lower-cost vehicle.
                index futures, forwards and other contracts — may be a
                reasonable alternative to a direct investment in the fund.      HOW CLOSE CAN WE COME to replicating hedge
                    Table 3 summarizes the empirical results of the expected-   fund returns? To answer this question, we construct linear
                return decomposition for our sample of funds, grouped ac-       clones of each fund in our sample by regressing the fund’s re-
                cording to their style categories. Each row contains the        turns on five of the six factors we considered above (we drop
                average total mean return of funds in a given category, and     the DVIX volatility factor because its returns are not as easily
                averages of the percent contributions of each of the six fac-   realized with liquid instruments) and no intercept, and then
                tors and the manager-specific alpha to that average total       rescaling the fitted regression equation so that the resulting
                mean return. For example, the most significant contributors      buy-and-hold portfolio has the same sample volatility as the
                to the investment return of convertible-arbitrage funds are     original fund’s return series. We omit the intercept because
                the dollar index (67.1 percent), the bond index (34.9 per-      our objective is to estimate a weighted average of the factors
                cent), the commodity index (31.8 percent) and the credit        that best replicates the fund’s returns. The motivation for
rescaling the volatility of the clones is to create a fair compar-     for the event-driven funds. This large gap is understand-
ison between the buy-and-hold portfolio and the fund, and              able, given the idiosyncratic and opportunistic nature of
is equivalent to changing the leverage of the clone portfolio.         most event-driven strategies. Moreover, a significant
    Table 4 contains a comparison of the performance of                source of the profitability of event-driven strategies is the
these linear clones and that of the original funds from which          illiquidity premium that managers earn through their
the clones are derived. The results are striking — for several         willingness to provide capital in times of distress. This
strategy categories the average mean return of the clones is           illiquidity premium will clearly be missing from a clone
only slightly lower than that of their fund counterparts, and          portfolio of liquid securities; therefore, we should expect
in some categories the clones outperform. For example, the             a significant performance gap in this case.
average mean return of the convertible-arbitrage clones is                 For dedicated short-bias funds, the average mean return
8.15 percent, and the corresponding figure for the actual               of the clones and the funds is 3.58 and 5.98 percent, respec-
funds is 8.41 percent. For long-short equity hedge funds,              tively. This may seem somewhat counterintuitive in light of
the average mean return for clones and funds is 13.94 and              the expected-return decomposition in Table 3, where we
14.59 percent, respectively. And in the multistrategy catego-          observed that dedicated short-bias funds were responsible
ry, the average mean return for clones and funds is 10.10              for more than 100 percent of the average total returns of
and 10.79 percent, respectively.                                       funds in this category. The fact that dedicated short-bias
    In three cases the average mean return of the clones is            clones have positive average performance is due entirely to
higher than that of the funds: global macro (14.43 percent             the clone of a single fund, No. 33735 in the TASS database,
versus 11.38 percent), managed futures (23.47 percent ver-             and when this outlier is dropped from the sample, the aver-
sus 13.64 percent) and fund of funds (8.63 percent versus              age mean return of the remaining nine clones drops to –0.35
8.25 percent). However, these differences are not statisti-            percent. The underperformance of the clones in this catego-
cally significant because of the variability in mean returns            ry is also intuitive — given the positive trend in the U.S.
across funds within each category. Even in the case of man-            stock market during the 1980s and ’90s, a passive strategy
aged futures, the difference in average mean return between            of shorting the S&P 500 is unlikely to have produced at-
clones and funds — almost 10 percentage points — is not                tractive returns when compared to the performance of more
statistically significant because of the large fluctuations in           nimble discretionary short-sellers.
average mean returns of the managed-futures clones. Nev-                   Another metric of comparison is the average Sharpe ratio,
ertheless, these results suggest that for certain categories,          which adjusts for the volatilities of the respective strategies.
the performance of clones may be within shouting distance              Given our rescaling process, the standard deviations for the
of their corresponding funds.                                          clones are identical to their fund counterparts, so a compari-
    One category of hedge funds that seems particularly                son of Sharpe ratios reduces to a comparison of mean re-
difficult to replicate is event-driven strategies. The aver-           turns. However, the average Sharpe ratio of a category is not
age performance of the event-driven clones, at 9.60 per-               the same as the ratio of that category’s average mean return
cent, is considerably lower than the 13.03 percent average             to its average volatility, so the Sharpe ratio statistics in Table
  Convertible arbitrage               82              8.4%           27.1%          67.1%         –19.3%         34.9%         –8.4%         31.8%          –33.3%
  Dedicated short-bias                10              6.0            12.2           19.4         –108.2           7.0           8.9         –64.9           225.6
  Emerging markets                   102              4.9            –0.3           –3.2           19.3           0.1          –0.4           6.2            78.3
  Equity market-neutral               83             20.4             0.2            3.6            4.0           3.9           1.3           6.3            80.8
  Event-driven                       169              8.1             2.1            3.0            4.3           9.4          –0.7           3.1            79.0
  Fixed-income arbitrage              62             13.0            –1.4            3.3            2.7          18.5          –0.5           4.4            73.1
  Global macro                        54              9.5             2.0            8.1            9.7          25.0          –3.3          10.0            48.6
  Long-short equity hedge            520             11.4             1.1            1.9           17.8           2.1          –1.8           8.4            70.5
  Managed futures                    114             14.6             1.9           23.4           –3.4          53.8          –1.5          53.2           –27.5
  Multistrategy                       59             13.6             0.5            3.5            5.7          10.1          –1.9           3.2            78.9
  Fund of funds                      355             10.8             0.5            5.4            9.7           8.8          –2.8           7.3            71.1
  All funds                        1,610              8.3             2.3            7.8            8.5          11.3          –1.9          10.9            61.0
                                                                                                                                       Source: Authors’ calculations.
                            4 do provide some incremental information. The average                    The clones have much lower average autocorrelations than
                            Sharpe ratio of the funds in the convertible-arbitrage cate-              their fund counterparts, with the exception of the managed-
                            gory is 2.70, which is almost twice the average Sharpe ratio              futures category, for which both clones and funds have very
                            of 1.54 for the clones, a significant risk-adjusted perform-               low average autocorrelations. For example, the average auto-
                            ance gap between the funds and their clones. However, there               correlation of convertible-arbitrage funds is 42.2 percent,
                            is virtually no difference in average Sharpe ratios between               and the corresponding average value for convertible-
                            clones and funds for equity market-neutral, long-short                    arbitrage clones is only 10.4 percent. A more formal statisti-
                            equity hedge and fund-of-funds categories. As we discussed                cal analysis shows that for every single category the average
                            above, the apparent similarity of dedicated short-bias clones             level of autocorrelation in the funds is higher than that in
                            to their funds is the result of a single outlier. And for global          the clones, confirming our intuition that, by construction,
                            macro and managed futures, the average Sharpe ratios of the               clones are more liquid than their fund counterparts.
                            clones are, in fact, higher than those of the funds.
                                Table 4 provides one more comparison worth noting: the                A PORTION OF EVERY HEDGE FUND’S expect-
                            average first-order autocorrelation coefficients of clones and              ed return is risk premiums — compensation to investors
                            funds. The first-order autocorrelation, ρ^ 1, is the correlation           for bearing certain risks. One of the most important
                            between a fund’s current return and the previous month’s re-              benefits of hedge fund investments is the nontraditional
                            turn, and in our previous studies we show that a positive val-            types of risks they encompass, such as tail risk, liquidity
                            ue for ρ^ 1 in hedge fund returns is a proxy for illiquidity risk.        risk and credit risk. Most investors would do well to take
 LINEAR CLONES
 Convertible arbitrage                82               8.15%             5.15%        6.20%         5.28%        1.54          0.62        10.4%               10.7%
 Dedicated short-bias                 10               3.58             13.09        28.27         10.05         0.16          0.54         1.2                 4.4
 Dedicated short-bias*                 9              –0.35              4.40        28.75         10.53         0.00          0.17         1.9                 4.2
 Emerging markets                    102              17.91             16.51        22.92         15.16         0.97          0.61         0.7                 8.8
 Equity market-neutral                83               7.45              6.81         7.78          5.84         1.14          0.76         1.8                 9.6
 Event-driven                        169               9.60              6.79         8.40          8.09         1.39          0.52         3.5                11.3
 Fixed-income arbitrage               62               8.55              6.04         6.56          4.41         1.43          0.64         2.5                 8.2
 Global macro                         54              14.43              9.65        11.93          6.10         1.25          0.55         3.9                 8.9
 Long-short equity hedge             520              13.94             10.34        15.96          9.06         0.96          0.59         0.1                 9.5
 Managed futures                     114              23.47             15.94        21.46         12.07         1.11          0.46         5.7                 8.5
 Multistrategy                        59              10.10              7.66         8.72          9.70         1.50          0.68         1.8                10.0
 Fund of funds                       355               8.63              5.88         6.36          4.47         1.46          0.48        –0.3                11.2
 ACTUAL FUNDS
 Convertible arbitrage                82               8.41%             5.11%        6.20%         5.28%        2.70          5.84         42.2%              17.3%
 Dedicated short-bias                 10               5.98              4.77        28.27         10.05         0.25          0.24          5.5               12.6
 Dedicated short-bias*                 9               4.92              3.58        28.75         10.53         0.20          0.20          3.4               11.3
 Emerging markets                    102              20.41             13.01        22.92         15.16         1.42          2.11         18.0               12.4
 Equity market-neutral                83               8.09              4.77         7.78          5.84         1.44          1.20          9.1               23.0
 Event-driven                        169              13.03              8.65         8.40          8.09         1.99          1.37         22.2               17.6
 Fixed-income arbitrage               62               9.50              4.54         6.56          4.41         2.05          1.48         22.1               17.6
 Global macro                         54              11.38              6.16        11.93          6.10         1.07          0.58          5.8               12.2
 Long-short equity hedge             520              14.59              8.14        15.96          9.06         1.06          0.58         12.8               14.9
 Managed futures                     114              13.64              9.35        21.46         12.07         0.67          0.39          2.5               10.2
 Multistrategy                        59              10.79              5.22         8.72          9.70         1.86          1.03         21.0               20.1
 Fund of funds                       355               8.25              3.73         6.36          4.47         1.66          0.86         23.2               15.0
 * Fund No. 33735 has been dropped from this sample of dedicated short-bias funds.                                                      Source: Authors’ calculations.
on small amounts of such risks if they are not already             nonlinearities in a buy-and-hold portfolio. In fact, an ear-
doing so because these factors usually yield attractive            lier study by Lo and Martin Haugh shows that a judi-
risk premiums, and many of these risks are not highly              ciously constructed buy-and-hold portfolio of simple put
correlated with those of traditional long-only invest-             and call options can yield an excellent approximation to
ments. Although talented hedge fund managers are al-               certain dynamic trading strategies, and this approach can
ways likely to outperform passive buy-and-hold                     also be used to create better clones.
portfolios, the challenges of manager selection and mon-               Finally, a number of implementation issues remain to
itoring, the lack of transparency, the limited capacity of         be resolved before hedge fund clones become a reality: the
such managers and the high fees may tip the scales for             estimation methods for computing clone portfolio
the institutional investor in favor of clone portfolios. In        weights, the implications of the implied leverage required
such circumstances, portable beta may be a reasonable              by our volatility rescaling process, the optimal rebalanc-
alternative to portable alpha.                                     ing interval, the types of strategies to be cloned and the
    Our empirical findings suggest that the possibility of         best method for combining clones into a single portfolio.
cloning hedge fund returns is real. For certain hedge fund         We are cautiously optimistic that the promise of our ini-
categories, the average performance of clones is compara-          tial findings will provide sufficient motivation to take on
ble — on both a raw-return and a risk-adjusted basis —             these practical challenges.
to that of their hedge fund counterparts. For other cate-
gories, like dedicated short-bias and event-driven, the
clones are less successful.
    As encouraging as these results may be, several qualifi-
cations must be kept in mind. First, we have used the
entire sample of return histories to construct our clones,
which is a particularly naive approach to replicating a
dynamic strategy and also imparts a “look-ahead bias” to
the results. Any practical cloning process must employ
rolling or expanding windows to estimate the portfolio
weights. This allows the clone-portfolio weights to change
over time and in response to changing market conditions,
a particularly important feature in the hedge fund con-
text. Although the look-ahead bias may not be that severe
in this case because we did not select the best-performing
clone among many trials, nevertheless, a more realistic
simulation is an important extension of our analysis.
    Second, despite the promising properties of linear clones
in several style categories, it is well known that certain hedge
fund strategies contain inherent nonlinearities that cannot
be captured by linear models (for example, Capital Multi-
plication Partners). Therefore, more sophisticated nonlinear
methods — including nonlinear regression, regime-switch-
ing processes, stochastic volatility models and Kat and
Palaro’s copula-based algorithm — may yield significant
benefits in terms of performance and goodness-of-fit. How-
ever, there is an important trade-off between goodness-of-fit
and the complexity of the replication process, and this trade-       Jasmina Hasanhodzic is a Ph.D. candidate in the Department of Electrical Engi-
off varies from one investor to the next. As more                    neering and Computer Science at the Massachusetts Institute of Technology. Andrew
sophisticated replication methods are used, the resulting            W. Lo is the Harris & Harris Group Professor of Finance at the MIT Sloan School
clone becomes less passive, requiring more trading and risk-         of Management and founder and chief scientific officer of AlphaSimplex Group, a
management expertise, and eventually becoming as com-                quantitative investment management company based in Cambridge, Massachusetts.
plex as the hedge fund strategy itself.                              The views and opinions expressed in this article are those of the authors only and do
    Third, the replicating factors we proposed are only a            not necessarily represent the views and opinions of AlphaSimplex Group, MIT or
small subset of the many liquid instruments that are avail-          any of their affiliates and employees. The authors make no representations or war-
able to the institutional investor. By expanding the uni-            ranty, either expressed or implied, as to the accuracy or completeness of the informa-
verse of factors to include options and other derivative             tion contained in this article, nor are they recommending that this article serve as
securities and customizing the set of factors to each hedge          the basis for any investment decision. For a complete list of references used in prepar-
fund category (and perhaps to each fund), it should be               ing this article, as well as a more detailed explanation of the analyses and addition-
possible to achieve additional improvements in perform-              al results and tables, please refer to Lo’s home page, web.mit.edu/alo/www.
ance, including the ability to capture tail risk and other