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Can Stochastic Discount Factor Models Explain the Cross Section of
Equity Returns?
Pongrapeeporn Abhakorna
Peter N. Smith
Fiscal Policy Office
Department of Economics and Related Studies
Ministry of Finance of Thailand
University of York, UK
Phayatai Road, Thailand, 10400
YO10 5DD
E-mail: peter.smith@york.ac.uk
E-mail: pongrapeeporn.a@mof.go.th
Tel.: +66851234466 Fax: +6626183374
Michael R. Wickens
Cardiff Business School and Department of Economics and Related Studies
University of York, UK
YO10 5DD
E-mail: mike.wickens@york.ac.uk
Abstract
We propose a multivariate test based on no-arbitrage conditions under the stochastic
discount factor approach, which compares cross-sectional variation in equity returns
to the cross-sectional variation in their conditional covariance with the discount
factors. Using the multivariate generalized heteroskedasticity in mean model to
estimate the 25 portfolios formed on size and book-to-market ratio, together each with
its own arbitrage condition, we find that the no-arbitrage test rejects the consumptionbased capital asset pricing model (C-CAPM). Although the conditional covariances of
returns with consumption exhibit negative variation across size, they do not vary
across the book-to-market ratio. Thus, the C-CAPM can capture size effect, but not
value effect. Allowing the coefficients on the consumption covariances to be different
largely improves the fit of the C-CAPM, however. The value effect appears to be
associated with book-to-market ratio as well as size. Book-to-market ratio separately
does not generate information about average returns that cannot be explained by the
C-CAPM. One possible explanation for this extra dimension of risk is the investment
growth prospect of firms. Low book-to-market ratio firms may be expected to have
higher rates of growth while small firms may also be expected to behave similarly.
JEL Classification: G12, G14, C32, E44
Keywords: Risk Premium; Equity Return; Stochastic Discount Factor; No-arbitrage
Condition
a
Corresponding author. The views expressed in the paper are those of the authors and do not
necessarily represent those of the Fiscal Policy Office.
1. Introduction
Size and value effects have long been recognized as “anomalies” both in the capital
asset pricing model (CAPM) literature (summarized in Fama and French, 2006 and
2008), and in the consumption-based CAPM (C-CAPM) framework with power
utility (see Cochrane, 2008). This paper tests whether stochastic discount factor (SDF)
models that satisfy no-arbitrage restrictions can explain the behavior of a cross section
of returns on 25 portfolios sorted by firm size and their book-to-market ratio ratio (the
25 Fama-French portfolios). We examine whether portfolios of stocks have different
returns due to different conditional covariances between the returns and the relevant
discount factors, or because the coefficients of the discount factors vary by portfolio
characteristic. This provides a test of no-arbitrage as finding either effect would imply
that no-arbitrage does not hold.
Instead of modelling separate no-arbitrage conditions for the returns on the
25 Fama-French portfolios, we model them simultaneously employing an SDF
framework.
We
use
a
multivariate
generalized
autoregressive
conditional
heteroskasticity in mean model (MGM) as in Smith and Wickens (2002). This
methodology is in contrast to most of the time-series econometric models of equity
returns in the literature, which are univariate models and do not include conditional
covariances (see for example Ludvigson, 2012). Smith, Sorensen, and Wickens (2008)
used the approach adopted in this paper, examining various SDF models, including
the standard C-CAPM, to generate models involving macroeconomic variables.
Abhakorn, Smith, and Wickens (2013) estimate the MGM for the standard C-CAPM
for each of the 25 Fama-French portfolios, and find that the fit of the model is
significantly improved by the inclusion of the firm book-to-market value ratio (HML)
factor. This paper extends their analysis by estimating the all 25 Fama-French
portfolio returns simultaneously and testing for each asset-pricing model whether the
conditional covariances of these returns with the relevant discount factors can
adequately explain the excess returns of these portfolios.
We find that C-CAPM is rejected by the no-arbitrage test. The model can
explain the size effect, as the conditional covariance of consumption with firm size is
negative, but not the value effect, as the conditional covariance of consumption with
2
the book-to-market ratio does not vary as required across the book-to-market
quintiles. We find that the value effect tends to be slightly lower for portfolios in the
highest book-to-market quintile - indicating that a lower risk premium - than for
portfolios with the lowest book-to-market quintiles. Allowing the coefficients on the
conditional covariances to vary across the portfolios improves fit markedly. As CCAPM restricts them to be the same, this too is an indication of the failure of the
model.
The paper is set out as follows. In Section 2, we briefly review the relevant
literature on CAPM and C-CAPM. In Section 3 we describe our theoretical
framework for asset pricing and in Section 4 we explain our econometric
methodology. In Section 5, we report our empirical results. Section 6 summarizes the
findings of this paper.
2. Some relevant literature on CAPM and C-CAPM
Evidence that the accounting variables firm size and the book-to-market ratio would
be significant if included in the standard CAPM in addition to the market return was
first
presented
by Fama and French (1993 and 2008). This cast doubt on the
empirical validity of the CAPM as it suggested that additional pricing factors to the
market return were required to successfully explain the cross-section of stock returns.
This raises the question of whether such anomalies would also be significant in
alternative models to CAPM such as C-CAPM which takes into account the
intertemporal nature of the investor optimization problem. Cochrane (2008) found
that size and value effects are not significant in C-CAPM
More recently, however, a number of studies have attempted to explain the crosssection of equity returns using modified versions of C-CAPM that included either
different or additional factors. Lettau and Ludvigson (2001) use the ratio of aggregate
consumption to wealth as a conditioning variable in C-CAPM in order to better
capture variations in expected returns over time. An alternative way to overcome the
slowness of the consumption adjustment process was suggested by Parker and Julliard
(2005) who measured the risk premium by its covariance with consumption growth
cumulated over many quarters after the return period, see also Jagannathan and Wang
(2007). Yogo (2006) proposed a two-factor model that includes nondurable and
3
durable consumption growth. He found that the size and value effects are due to
small and value stocks having higher durable consumption betas than large and
growth stocks. Savov (2011) suggested the use of household garbage production as a
proxy for consumption; as all forms of consumption produce waste, garbage growth
should be informative about rates of consumption growth. These modified versions of
C-CAPM seem to explain the cross-section of equity returns equally well to the Fama
and French three-factor model (Fama and French, 1993). In this paper, rather than
asserting that there are alternative or missing factors
in C-CAPM, we exploit
implications of C-CAPM that are ignored in the papers discussed above while keeping
close to the ideas of Fama and French. In particular, we include the two additional
factors of Fama and French, and do so using C-CAPM instead of CAPM, Thus we
explore the validity of the model but in a multivariate no-arbitrage framework by
estimating the 25 Fama-French portfolios simultaneously.
It appears from the results of Abhakorn, Smith, and Wickens (2013) that in
order to capture the value effect using C-CAPM it is necessary to include both firm
size and the book-to-market ratio as when including them individually C-CAPM
cannot explain small growth portfolios. They find that HML helps explain the 25
Fama-French portfolios across size quintiles as well as across book-to-market ratio
quintiles, and suggest that HML may be associated with the investment growth
prospects of firm. This could be the reason why the investment-based asset pricing
models of Brennan, Wang, and Xia (2004) and Li, Vassalou, and Xing (2006) are able
to explain well the cross-section of equity returns but traditional CAPM is not able to
(e.g. Fama and French, 1992 and 2006 and Lewellen and Nagel, 2006). This suggests
that consumption contains information about these firm characteristics that is not
available through market return.
3. Theoretical Framework
3.1 Stochastic Discount Factor Representations of Asset Pricing Models
The basic no-arbitrage pricing equation for a risky asset defines a relationship
between the Stochastic Discount Factor (SDF) M t 1 and the risky return, Rt 1 .
1 Et [ M t 1Rt 1 ]
4
(1)
where M t 1 is the real stochastic discount factor for period t 1 and for equity, the
rate of return in real terms is Rt 1 ( Pt 1 Dt 1 ) / Pt , where Dt 1 are real dividend
payments assumed to be made at the start of period t 1 and Pt is the real price of
equity (see Cochrane, 2008). If the logarithms of M t 1 , Rt 1 and the risk free rate
( mt 1 , rt 1 , rt f ) are jointly normally distributed, then (1) implies that the expected
excess real return on equity is given by
1
Et (rt 1 rt f ) Vt (rt 1 ) Covt (mt 1 , rt 1 ) .
2
(2)
where the right-hand side is the risk premium and the variance term is the Jensen
effect.
Equation (2) can also be expressed in terms of nominal returns. If it 1 is the
nominal return on equity, it f is the nominal risk-free rate, Pt c is the consumer price
index, and inflation is 1 t 1 Pt c1 / Pt c , the pricing equation (1) becomes
1 Et M t 1 ( Pt c / Pt c1 )(1 it 1 ) .
The no-arbitrage condition for nominal returns is:
1
Et (it 1 it f ) Vt (it 1 ) Covt (mt 1 , it 1 ) Covt ( t 1 , it 1 ) .
2
(3)
Comparing (3) and (2), the no-arbitrage condition for the nominal return involves one
additional term in the conditional covariance of returns with inflation.
More generally, if mt can be represented as a linear function of n 1 factors
zi ,t i 1,..., n 1 so that mt in11i zi ,t , then a general representation of (3) is
Et (it 1 it f ) 0Vt (it 1 ) in1i Covt ( zi ,t 1 , it 1 ) ,
(4)
where zn ,t t . The differences between many asset pricing models are in their
stochastic discount factor, zi ,t 1 , and the restrictions imposed on the coefficients. We
consider three pricing models that are special cases of equation (4):
(a) C-CAPM with power utility
The discount factor in this case is M t 1 C t 1 / Ct where the consumer./investor
has utility function, U (Ct ) (Ct1 1) /(1 ) over real expenditure Ct with
constant coefficient of relative risk aversion (CRRA). The nominal no-arbitrage
condition in this case is:
5
1
Et (it 1 it f ) Vt (it 1 ) Covt ( ln Ct 1 , it 1 ) Covt ( t 1 , it 1 ) ,
2
(5)
where ln Ct 1 Ct 1 / Ct is the growth rate of consumption. C-CAPM with power
utility implies that excess returns of different portfolios of equities differ due to their
conditional covariance with consumption with a common CRRA.
(b) CAPM
The CAPM implies that the expected return of an asset must be linearly related to the
covariance of its return with the return on the market portfolio through
Et ( rt 1 rt f ) t Covt ( rt m1 , rt 1 )
where t Et ( rt m1 rt f ) / Vt ( rt m1 ) is the market price of risk and can be interpreted as
the CRRA (Merton, 1980). There is no Jensen effect because log-normality is not
assumed. The corresponding no-arbitrage condition for nominal returns is
Et (it 1 it f ) t Covt (itm1 , it 1 )
(6)
where itm1 is the nominal return on the market portfolio.
(c) General Stochastic Discount Factor Models
General SDF models are based on macroeconomic factors and particular versions of
the multifactor model in (4) which also allow the factors to have unrestricted
coefficients. We consider general SDF model with up to three macroeconomic factors.
Smith, Sorensen, and Wickens (2008) suggest the use of factors that are associated
with the business cycle and inflation. They argue that as financial institutions, such as
pension funds, are the main holders of equity and act on behalf of investors and often
focus on short-term business cycle considerations rather than on longer term
performance associated with the utility of their investors. The authors, therefore, use
output growth as an additional source of risk to consumption and inflation, but
without seeking to give the model a general equilibrium interpretation.
3.2 Testing the Discount Factor Models
In all of the SDF models previously discussed, the discount factors are functions of
aggregate variables, and thus it is possible to hold the properties of the discount
factors constant as one individual asset is compared to another. As the risk premium is
represented by the conditional covariance of the returns with the discount factor, we
can compare cross-sectional average returns with cross-sectional variation in their
6
conditional covariances with the factors. The implication is that the coefficients on
these conditional covariances should be the same across the cross-section of equity
returns and stocks have different returns because they have different conditional
covariances with the relevant factors. Our estimation method allows these covariances
also to vary through time. This relation provides testable restrictions on no-arbitrage
conditions, and therefore, it can be interpreted as a no-arbitrage test.
Table 1 provides a summary of restrictions for each asset pricing models
implied by its no-arbitrage condition. C-CAPM with power utility and nominal
returns (M1) implies that the CRRA is constant and should be the same across the
cross-section of expected returns for no arbitrage opportunities in the market. M1 is
the restricted version of C-CAPM. On the other hand, allowing the coefficients on the
conditional covariances of returns with consumption to be different generates an
unrestricted version of C-CAPM (M4). The double-sorted, 25 size and book-tomarket equity ratio portfolios generate two more versions of C-CAPM with power
utility: restricted book-to-market model (M2) and restricted size model (M3). M2
allows portfolios with different size groups to have different coefficients on the
consumption covariances, while M3 allows the coefficients for portfolios with
different book-to-market-equity ratio groups to be different. Similarly, these
restrictions of C-CAPM are applied to the CAPM, where the market price of risk is
expected to be the same across assets, (M5-M8). In addition, the restricted and
unrestricted general SDF models, based on two (consumption growth and inflation)
and three macroeconomic variables (consumption growth, inflation and industrial
production growth), are given by M9-M12. In sum, all the above asset pricing models
can be represented as restricted versions of the SDF model,
Et (itsb1 it f ) 0,sbVt (itsb1 ) 1,sbCovt (ct 1 , itsb1 ) 2,sbCovt ( t 1 , itsb1 )
3,sbCovt (qt 1 , itsb1 ) 4,sbCovt (itm1 , itsb1 )
(7)
where s and b indicate size and book-to-market ratio groups that the characteristics
portfolios belong to, respectively, and qt is industrial production. The different asset
models can be obtained by placing different restrictions on the i , s, and b.
7
Table 1
Restrictions on the No-arbitrage Condition
s and b indicate size and book-to-market groups for the characteristics portfolios. The numbers are in
ascending order of magnitude. The smallest size is denoted by s = 1 while the lowest book-to-market
ratio is represented by b = 1.
denotes constant coefficient of relative risk aversion (CRRA).
i
represents a coefficient for each conditional covariance in Equation 8.
0
Models
M1: C-CAPM with power utility and nominal return
M2: Restricted book-to-market C-CAPM
M3: Restricted size C-CAPM
M4: Unrestricted C-CAPM
1
2
1
2
1
2
1
2
1
2
3
4
1
0
0
1,s
1
0
0
1,b
1
0
0
1,sb
1
0
0
M5: CAPM
0
0
0
0
M6: Restricted book-to-market CAPM
0
0
0
0
4,s
M7: Restricted size CAPM
0
0
0
0
4,b
M8: Unrestricted CAPM
0
0
0
0
4,sb
1
2
1
2
1
2
1
2
1
2
0
0
1,sb
2,sb
0
0
1
2
3
0
1,sb
2,sb
3,sb
0
M9: Restricted two-factor SDF model
M10: Unrestricted two-factor SDF model
M11: Restricted three-factor SDF model
M12: Unrestricted three-factor SDF model
8
4. Econometric Framework
We follow the same econometric approach here as in Smith and Wickens (2002), and
Smith, Sorensen, and Wickens (2008, 2010), and Abhakorn, Smith, and Wickens
(2013)
by
using
the
multivariate
generalized
autoregressive
conditional
heteroskedasticity in mean model (MGM) to estimate the joint distribution of the
excess return on equity with macroeconomic factors in such a way that the return
satisfies the no-arbitrage condition under the SDF framework. This approach is
achieved by including conditional covariances of the excess equity returns and the
macroeconomic factors in the mean of the asset pricing equations and constraining the
coefficients on these time-varying, conditional covariances according to the noarbitrage condition implied by each asset-pricing model.
Let xt 1 (r1,t 1 rt f ,..., ri ,t 1 rt f , ct 1 , t 1 , qt 1 ) ' which contains n variables and i
returns, as several portfolios are estimated at the same time. This specification is an
extension of the MGM in Smith and Wickens (2002). Consumption, inflation, and
industrial productions are included, as they give rise to the discount factors in the SDF
model, M1-M12 in Table 1, through their conditional covariances with the excess
returns. Additional macroeconomic variables can be included in this vector if they
improve the estimate of the joint distribution. The MGM model can then be written as
x t+1 =
+ xt +
g t+1 +
t+1
,
where
t+1
| It ~ N (0, Ht+1 ) ,
gt+1 vech(Ht+1 ) .
where,
is a n n matrix of coefficients in the
is a n 1 vector of constant,
vector autoregressive (VAR) part (included to obtain better representation of the error
terms),
is a n n matrix of coefficients of in-mean component,
t+1
is an n 1
vector of errors, and i number of equity returns. The vech operator converts the
lower triangle of a symmetric matrix into a vector. The error term,
t+1
, is
conditionally normally distributed with mean zero and with conditional covariance
matrix Ht+1 . The first i rows of the model is restricted to satisfy the no-arbitrage
condition as follows: 1) the first i rows of
must be zero; 2) the first i rows of
depends on then specification of each asset pricing model defined in Table 1; 3) the
9
i+1 to i+3 rows of
are all zero; and 4) the first i elements of
is zero. A
likelihood ratio test is used to provide test statistics for the restrictions implied by the
no-arbitrage condition in M1-M12 as given in Table 1.
While the MGM model is convenient, it is heavily parameterized, which can create
numerical problems in finding the maximum of the likelihood function due to the
likelihood of being relatively flat, and hence uninformative. Therefore, to complete
the model parameterization for the conditional covariance matrix Ht+1 with the view
toward restricting the number of coefficients being estimated, the specification of the
conditional covariance matrix is chosen to be the vector diagonal model with variance
targeting (Ding and Engle, 2001), which can be written as follows,
H t+1 H 0 (ii / - aa / - bb / ) aa / (
/
t t
) bb / H t
where denotes Hadamard product, H 0 is the observed sample covariance matrix,
and a and b are n 1 vectors. The number of parameters to be estimated reduces to
2n . This model is particularly attractive when we estimate several excess returns
simultaneously, each with its own arbitrage condition. In addition, the zero
restrictions on the coefficients for excess returns in the VAR part of the
macroeconomic variables are imposed to further reduce the number of parameters in
the MGM model. Estimating the restricted and unrestricted C-CAPM (M1 and M4)
for the 25 portfolios sorted by size and book-to-market ratio involve 69 and 93
parameters, respectively, while for the CAPM (M5 and M8) involving 53 and 78
parameters; we need to include only the market return, instead of the macroeconomic
factors, in the joint distribution. We are unable to estimate M10 and M12 for the 25
portfolios, as doing so involves estimating too many parameters for our sample size
(118 and 143 parameters, respectively); hence we include the two data sets of the 10
portfolios formed for size and book-to-market ratio separately to test for these general
two- and three-factor SDF models, in addition to using these one-sorted portfolios to
contrast the estimation results with the two-characteristics-sorted portfolios.
10
5. Estimation Results
5.1 Data
The data are monthly from 1960.2 to 2004.11 for the U.S. (538 observations). The
return on the market portfolio is the value-weighted return on all stocks. The return on
a risk-free asset is the one-month Treasury bill rate. Table 2 shows the summary
statistics for the 25 value-weighted portfolios, which are the intersections of 5
portfolios formed on size and 5 portfolios formed on the ratio of book-to-market ratio.
There are also two sets of ten portfolios sorted by size and book-to-market ratio
separately (Table 3). All of the return variables are obtained from Kenneth French’s
websiteb. Real non-durable growth consumption is from the Federal Reserve Bank of
St. Louis. CPI inflation and the volume index of industrial production are both from
Datastream.
b
http://mba.tuck.dartmouth.edu/pages/faculty/ken.french/data_library.html
11
Table 2
Summary Statistics: 25 Size and Book-to-Market Portfolios
The table presents descriptive statistics for the excess returns on the 25 portfolios formed as the
intersections of the five size and book-to-market ratio groups. Data and full definition of the returns can
be found on Kenneth French’s webpage. The returns are monthly value-weighted from 1960.2 to
2004.11, 538 observations. t-stat is the test statistics for zero mean hypothesis. ( xt , x t-i ) represents
the autocorrelation coefficients over the time interval i month (s).
Book-to-Market Equity Quintiles
Size
Quintiles
Low
Small
2
3
4
Big
-0.07
0.10
0.18
0.34
0.30
Small
2
3
4
Big
-0.53
-0.70
-0.65
-0.49
-0.46
Small
2
3
4
Big
72.7
50.7
44.8
46.9
44.2
Small
2
3
4
Big
37
173
413
1068
9511
Small
2
3
4
Big
0.65
0.94
1.71
3.72
36.21
Small
2
3
4
Big
0.20
0.16
0.12
0.11
0.06
Small
2
3
4
Big
0.02
0.02
0.02
0.02
-0.03
2
3
4
Mean
0.54
0.66
0.90
0.47
0.72
0.82
0.58
0.57
0.73
0.38
0.63
0.75
0.39
0.46
0.47
Skewness
-0.46
-0.60
-0.59
-0.89
-0.92
-0.81
-0.99
-0.95
-0.59
-0.96
-0.75
-0.32
-0.62
-0.53
-0.15
Normality
110.0
111.1
144.2
90.1
104.7
107.4
94.7
79.9
84.4
112.3
98.4
46.5
62.0
92.6
27.5
Average firm size
39
38
34
175
177
176
421
421
424
1063
1070
1079
7119
6166
5052
Average percent of market value
0.44
0.43
0.46
0.69
0.69
0.63
1.27
1.18
1.00
2.79
2.38
1.98
16.87
11.29
7.43
( x t , x t 1 )
0.18
0.20
0.20
0.16
0.17
0.16
0.15
0.16
0.16
0.13
0.11
0.08
0.04
0.00
-0.02
( xt , xt 6 )
0.03
0.03
0.02
0.01
0.02
0.02
0.01
0.02
-0.01
0.01
-0.03
-0.03
-0.06
-0.04
-0.06
High
Low
0.97
0.89
0.83
0.70
0.49
8.20
7.48
6.86
6.04
4.80
-0.58
-0.76
-0.80
-0.52
-0.36
2.72
2.34
2.07
1.99
1.89
137.7
117.5
124.4
73.3
23.8
-0.18
0.29
0.60
1.29
1.45
26
172
431
1075
4643
0.28
0.28
0.27
0.27
0.26
0.56
0.48
0.71
1.31
4.17
492
152
115
97
106
0.24
0.15
0.14
0.07
0.06
-0.06
-0.07
-0.05
-0.04
0.03
-0.01
-0.01
-0.01
-0.03
0.02
0.00
-0.03
-0.03
-0.03
0.05
12
2
3
4
Standard deviation
6.98
5.97
5.56
6.07
5.36
5.14
5.44
4.92
4.75
5.15
4.83
4.61
4.54
4.29
4.19
Excess Kurtosis
3.38
3.72
4.35
4.03
4.56
4.23
4.52
3.85
3.12
4.93
3.86
1.82
2.60
3.18
1.23
t-statistics for zero mean
1.78
2.56
3.74
1.81
3.13
3.72
2.48
2.68
3.58
1.73
3.02
3.77
2.00
2.50
2.62
Average book-to-market ratio
0.57
0.78
1.03
0.54
0.76
1.005
0.54
0.75
1.004
0.55
0.75
1.03
0.53
0.75
1.004
Average number of firms
312
315
376
110
109
99
84
78
66
73
62
51
66
51
41
( xt , xt 3 )
-0.09
-0.05
-0.04
-0.05
-0.05
-0.05
-0.01
-0.05
-0.02
-0.04
-0.02
0.01
-0.01
-0.02
0.02
( x t , x t 12 )
0.02
0.06
0.08
0.03
0.05
0.08
0.03
0.02
0.04
0.00
0.03
0.06
0.01
0.02
0.02
High
5.85
5.73
5.36
5.35
4.78
4.20
4.32
4.63
2.72
1.17
3.84
3.60
3.59
3.05
2.37
1.85
1.70
1.66
1.70
1.50
603
77
46
34
25
-0.04
-0.05
-0.04
-0.04
-0.01
0.13
0.10
0.08
0.06
0.02
Table 3
Summary Statistics: 10 Industry Portfolios and Explanatory Variables
The table presents descriptive statistics for the returns on the 10 portfolios and explanatory variables.
The returns are monthly value-weighted from 1960.2 to 2004.11, 538 observations. Data and full
definition of the 10 portfolios can be found on Kenneth French’s webpage. im,t+1 and itf are the returns
on the market portfolios and one-month Treasury bill rate respectively. Consumption growth, inflation,
and industrial production growth are represented by ct+1, t+1, and qt+1 respectively. Std. Dev is the
standard deviation. t-stat is the t-statistic for zero mean hypothesis. t-stat is the test statistics for zero
mean hypothesis. ( xt , x t-i ) represents the autocorrelation coefficients over the time interval i
month(s). BM denotes book-to-market equity ratio. Firm size, book-to-market equity ratio, percent of
the market, and number of firms are in average terms.
Mean
Std. Dev.
Skewness
Excess Kurtosis
Normality
t-stat
Firm Size
% of Market
No. of firms
( x t , x t 1 )
( xt , xt 3 )
( xt , xt 6 )
( x t , x t 12 )
Mean
Std. Dev.
Skewness
Excess Kurtosis
Normality
t-stat
Firm Size
BM
% of Market
No. of firms
( x t , x t 1 )
( xt , xt 3 )
( xt , xt 6 )
( x t , x t 12 )
Mean
Small
1.04
6.32
-0.53
3.23
94.89
3.81
21
1.47
2123
0.24
2
0.98
6.26
-0.64
3.52
96.69
3.64
78
1.37
523
0.17
3
1.03
5.99
-0.78
3.22
72.24
3.98
139
1.62
347
0.16
4
0.98
5.80
-0.86
3.56
77.02
3.91
219
2.00
272
0.16
Size Deciles
5
6
1.01
0.92
5.55
5.25
-0.85
-0.84
3.42
3.20
73.66
68.42
4.23
4.08
338
512
2.59
3.33
229
194
0.14
0.01
7
0.98
5.11
-0.71
3.33
81.48
4.45
803
4.69
175
0.12
8
0.95
4.98
-0.64
2.49
56.85
4.41
1346
7.39
164
0.09
9
0.91
4.54
-0.56
2.45
52.81
4.64
2597
13.23
152
0.08
Large
0.79
4.26
-0.52
2.13
50.40
4.29
12780
62.31
146
0.01
-0.05
-0.07
-0.07
-0.06
-0.05
-0.04
-0.03
-0.04
-0.03
0.03
0.01
0.02
0.01
0.02
0.02
0.01
0.00
0.00
-0.02
-0.03
0.08
0.04
0.03
0.03
0.01
0.01
0.01
0.01
0.01
0.05
Book-to-market Deciles
5
6
7
0.93
0.99
1.05
4.35
4.36
4.26
-0.70
-0.67
-0.17
4.24
3.54
1.80
121.46
93.76
50.24
4.96
5.27
5.71
723
576
527
0.71
0.82
0.94
7.79
6.20
5.76
308
307
312
0.05
0.03
0.04
8
1.09
4.26
-0.28
2.11
60.74
5.93
433
1.10
4.88
322
0.05
9
1.12
4.64
-0.41
2.11
54.66
5.59
349
1.35
4.29
351
0.09
High
1.21
5.33
-0.37
3.26
112.13
5.25
177
2.03
2.68
433
0.12
Low
0.67
5.24
-0.42
1.67
38.09
2.91
1582
0.20
32.80
592
0.09
2
0.85
4.77
-0.69
2.76
63.18
4.14
1178
0.37
15.27
370
0.07
3
0.87
4.73
-0.81
3.88
92.12
4.28
981
0.49
11.46
333
0.07
4
0.86
4.66
-0.66
3.12
78.47
4.28
813
0.60
8.88
312
0.08
0.02
-0.01
-0.02
-0.03
-0.04
0.01
0.02
-0.01
-0.03
-0.03
-0.02
-0.01
-0.04
-0.04
-0.03
0.00
-0.06
-0.03
-0.02
-0.02
0.02
0.02
0.01
0.01
0.02
0.02
0.01
0.07
0.06
0.07
im , t 1
it f
c t 1
t 1
0.94
0.46
0.23
0.35
Explanatory variables
q t 1
Std. Dev.
4.41
0.23
0.73
0.30
0.75
Skewness
-0.46
1.041
-0.04
0.99
-0.62
Excess Kurtosis
Normality
( x t , x t 1 )
( xt , xt 3 )
( xt , xt 6 )
( x t , x t 12 )
im , t 1
0.25
1.90
1.70
1.37
1.68
2.98
44.85
98.95
33.56
82.25
75.70
0.06
0.95
-0.36
0.64
0.36
0.00
0.90
0.14
0.53
0.27
-0.02
0.84
0.01
0.52
0.09
0.02
0.72
-0.07
0.44
-0.04
13
it
f
Correlation
it f
c t 1
t 1
-0.04
1.00
c t 1
0.15
-0.09
1.00
t 1
q t 1
-0.14
0.54
-0.20
1.00
-0.03
-0.16
0.14
-0.10
q t 1
1.00
The descriptive statistics for the excess returns for the 25 portfolios in Table 2 are
similar to those in Fama and French (1993 and 2006) for the periods 1963-1991 and
1963-2004 respectively, thus indicating the value effect and relatively weak size
effect. This relatively weak size effect is also seen in Table 3 where one-characteristic
sorted portfolios are considered. In general, all excess returns and macroeconomic
variables appear to have negative skewness, excess kurtosis, and non-normality,
except for the risk-free rate and inflation, which display positive skewness and show
persistent volatility.
5.2 Estimates
5.2.1 C-CAPM
A full set of model estimates with their restricted versions for C-CAPM with power
utility and nominal returns is reported in Table 4. A likelihood ratio test is used to
examine the hypothesis implied by each restricted model against the unrestricted
model, M4. For M1, the conditional covariance of returns with consumption is highly
significant, but the size of the coefficient, 83.25, implies an implausibly large CRRA,
which is a common feature of consumption-based models (Campbell, 2002,
Cochrane, 2008, Yogo (2006), Smith, Sorensen, and Wickens, 2008, 2010) except for
C-CAPM with garbage growth of Savov (2011).
For M2, all five consumption coefficients are significant, and the likelihood ratio
rejects the hypothesis that portfolios within different book-to-market equity ratio
quintiles have the same coefficient at any conventional levels. The test statistic for the
restrictions against the unrestricted model M4 is close to that for M1, implying that
the differences in the coefficients across size have little weight on the behavior of the
estimated returns. On the other hand, the likelihood ratio test marginally fails to reject
M3 ( p value 0.0513); restricting the consumption coefficients for portfolios within
the same size quintiles to be the same does not exclude significant information about
the excess returns. In other words, size has no, or a relatively weak, relation to the
consumption coefficient. In fact, the coefficients in M2 for each size quintile look
very similar, while those in M3 for each book-to-market equity ratio quintiles increase
substantially from the lowest to the highest book-to-market quintiles. In addition, the
14
consumption covariance coefficient for the lowest book-to-market equity ratio
quintiles in M3 is not significantly different from zero.
M4 has 23 coefficients that are significant at conventional significance levels. All
coefficients range widely from 47.79 to 247.14. Looking down each column, there is
no clear pattern in the values of the coefficients across the size quintiles, whilst when
looking across each row; the coefficients tend to rise as the book-to-market ratio
increases. Like the insignificance of the consumption coefficient on the lowest bookto-market quintile in M3, the remaining 2 coefficients for the lowest book-to-market
quintile and the first 2 smallest size quintiles are not significantly different from zero.
The insignificance of the coefficients for the lowest book-to-market quintiles of the 25
portfolios is consistent with the evidence from other empirical asset pricing studies on
the 25 portfolios (Fama and French, 2008, Lettau and Lugvigson, 2001, Parker and
Julliard, 2005, Yogo, 2006, and Savov, 2011) where the pricing models they propose
also have difficulty explaining the portfolios in the smallest size and lowest book-tomarket quintiles (small growth portfolio). This inability may be due to limits to
arbitrage from short-sale constraints for these portfolios, and thus frictionless
equilibrium models, including C-CAPM, cannot explain the returns on these small
growth portfolios (Yogo, 2006).
Figure 1 shows a scatter plot of average actual and estimated excess returns in M1
to M4 for the 25 portfolios. If the pricing model fits the data well, the points should
all lie on a 45-degree line. In Figure 1(d), M4 appears to best explain the excess return
on these portfolios and is more or less as good as the modified versions of C-CAPM
and the Fama and French three-factor model. The differences in the estimated risk
premium and actual excess return ranges from 0.01% to 0.18% per month, which is
lower than those in M1-M4.
Figures 1(a) and 1(b) show that the estimated risk premia from M1 and M2 are
similar, implying that imposing the restrictions on size quintiles does not affect the
behavior of risk premia. On the other hand, allowing the consumption coefficients to
be different, as in M3, improves the performance of the model sharply, except for the
5 portfolios in the lowest book-to-market ratio quintiles. This observation suggests
15
that book-to-market equity ratio seems to have additional information about the
average excess returns that is not captured by C-CAPM.
Table 4
Estimates of C-CAPM
The table presents the estimates of the C-CAPM (M1-M4): 1960.2-2004.11, 538 observations.
denotes the coefficient relative risk aversion and i represents a coefficient for each conditional
covariance in Equation 8. t ( ) and t(i ) are their corresponding t–statistics respectively. The pricing
models (M1-M4) are tested against each other using the log-likelihood ratio test. 2log represents the
likelihood ratio statistic. The corresponding p-value at 5% significance level is denoted by p-value.
1s
t ( 1 s )
2 lo g
p va lu e
1b
t ( 1b )
2 lo g
p va lu e
Size
Quintiles
Small
2
3
4
Big
1s
t ( 1 s )
1b
t ( 1b )
t ( )
83.25
4.11
Small
93.83
4.13
87.27
0.0000
Low
11.49
0.40
31.31
0.0513
Low
Panel A: 25 Size and Book-to-Market Portfolios
Panel A1: Restricted C-CAPM (M1)
2 lo g
p va lu e
89.30
0.0000
Panel A2: Restricted Book-to-Market C-CAPM (M2)
Size Quintiles
2
3
4
Big
81.83
80.50
80.57
87.62
3.89
3.73
3.58
2.62
Panel A3: Restricted Size C-CAPM (M3)
Book-to-Market Quintiles
2
3
4
High
62.46
100.51
130.99
128.32
2.76
4.31
5.53
5.64
2
3
sb
145.27
155.03
146.79
146.63
190.97
47.79
66.32
93.06
108.03
139.19
106.31
104.24
119.64
129.48
171.24
81.96
t ( )
2 lo g
3.29
16.71
Small
141.11
3.88
2
121.66
3.68
Panel A4: Unrestricted C-CAPM (M4)
Book-to-Market Quintiles
4
High
Low
2
183.46
167.67
0.90
2.55
171.43
164.63
1.46
2.76
177.21
176.68
1.86
3.55
169.83
142.16
2.21
2.82
175.10
247.14
2.16
2.75
Panel B: 10 Size Portfolios
Panel B1: Restricted C-CAPM (M1)
t ( )
7.93
5.96
Low
215.24
4.18
2
235.78
5.42
3
249.82
5.51
2 lo g
4
High
3.32
4.07
3.73
3.97
3.22
4.47
4.70
4.65
4.44
3.35
4.66
4.61
4.45
3.83
3.43
8
153.18
4.31
9
176.75
4.44
Large
181.85
4.01
8
279.32
7.82
9
254.01
6.99
High
250.89
7.33
p va lu e
0.0534
Panel B2: Unrestricted C-CAPM (M4)
Size Deciles
3
4
5
6
7
133.98
124.19
133.63
143.53
137.74
4.06
3.96
4.32
4.26
4.32
Panel C: 10 Book-to-Market Portfolios
Panel C1: Restricted C-CAPM (M1)
261.78
3
t ( sb )
p va lu e
0.7439
Panel C2: Unrestricted C-CAPM (M4)
Book-to-Market Deciles
4
5
6
7
252.10
267.28
270.21
272.45
5.88
5.89
6.72
7.44
16
Figure 1
Cross-Sectional Fit: C-CAPM for the 25 Size and Book-to-Market Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 25 size and bookto-market portfolios. The estimated models are (a) M1, (b) M2, and (c) M3, and (d) M4. The average
excess returns are adjusted for the Jensen effect.
(b) M2: Restricted Book-to-Market C-CAPM
1.4
1.2
1.2
1.0
1.0
Predicted Risk Premium
Predicted Risk Premium
(a) M1: Restricted C-CAPM
1.4
0.8
0.6
0.8
0.6
0.4
0.4
0.2
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0
0.0
1.4
0.2
0.4
Average Excess Return
1.2
1.2
1.0
1.0
0.8
0.6
0.2
0.2
0.6
0.8
1.2
1.4
1.2
1.4
0.6
0.4
0.4
1.0
0.8
0.4
0.2
0.8
(d) M4: Unrestricted C-CAPM
1.4
Predicted Risk Premium
Predicted Risk Premium
(c) M3: Restricted Size C-CAPM
1.4
0.0
0.0
0.6
Average Excess Return
1.0
1.2
0.0
0.0
1.4
Average Excess Return
0.2
0.4
0.6
0.8
1.0
Average Excess Return
We estimate M1 and M4 for the two one-characteristic sorted portfolios to
investigate whether these provide similar information to the double-sorted portfolios.
Panels B and C in Table 4 show that C-CAPM with power utility performs better, as
neither of the M1 is rejected, suggesting that sorting stocks according to size and
book-to-market ratio may more accurately distinguish stocks. For the 10 size
portfolios, all coefficients on the consumption covariances in M4 are significant, and
the model fits the data better than M1 (Figure 2). This is also true for the 10 book-tomarket ratio portfolios (Figure 3). In addition, the consumption coefficient for the
portfolio in the lowest book-to-market quintile is highly significant, while those for
17
the small growth portfolios in the 25 portfolios are not. The descriptive statistics in
Table 2 show that the average book-to-market ratios for these two portfolios are
similar, while their average firm sizes are very different. Firms in the smallest size
and the lowest book-to-market quintiles seem to be much smaller than other firms in
the lowest book-to-market quintiles. Therefore, additional information that is not
captured by C-CAPM may be associated with both book-to-market equity ratio as
well as size. One possible explanation is that this extra dimension of risk arises from
the investment growth prospect of firms. Abhakorn, Smith, and Wickens (2013) find
that, in the C-CAPM framework, the mimicking return factor related to book-tomarket ratio (HML) can explain the 25 Fama-French portfolios across size quintiles as
well as across book-to-market ratio quintiles. In this regard, they assert that HML may
represent risk associated with the investment growth prospects of firm as low book-tomarket ratio firms may be expected to have higher rates of growth while small firms
may also be expected to behave similarly. This interpretation of the extra dimension
of risk is also consistent with Brennan, Wang, and Xia (2004) and Li, Vassalou, and
Xing (2006). These two studies propose asset pricing models based on investment
related factors that can explain the cross-section of equity returns well.
Figure 2
Cross-Sectional Fit: C-CAPM for the 10 Size Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 10 size portfolios.
The estimated models are (a) M1 and (b) M4. The average excess returns are adjusted for the Jensen
effect.
(b) M4: Unrestricted C-CAPM
1.2
1.2
1.0
1.0
Predicted Risk Premium
Predicted Risk Premium
(a) M1: Restricted C-CAPM
0.8
0.6
0.4
0.2
0.2
0.8
0.6
0.4
0.4
0.6
0.8
1.0
0.2
0.2
1.2
Average Excess Return
0.4
0.6
0.8
Average Excess Return
18
1.0
1.2
Figure 3
Cross-Sectional Fit: C-CAPM for the 10 Book-to-Market Ratio Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 10 book-tomarket ratio portfolios. The estimated models are (a) M1 and (b) M4. The average excess returns are
adjusted for the Jensen effect.
(b) M4: Unrestricted C-CAPM
1.4
1.3
1.3
1.2
1.2
Predicted Risk Premium
Predicted Risk Premium
(a) M1: Restricted C-CAPM
1.4
1.1
1.0
1.1
1.0
0.9
0.9
0.8
0.8
0.7
0.7
0.8
0.9
1.0
1.1
1.2
1.3
0.7
0.7
1.4
Average Excess Return
0.8
0.9
1.0
1.1
1.2
1.3
1.4
Average Excess Return
5.2.2 CAPM
Table 5 reports the estimation results for all versions of CAPM. The market price of
risk in M5 is 2.77 with a t-statistics of 2.94 and is lower than those reported in earlier
related studies for the U.S. market (Harvey (1989) and Ng (1991)). Comparing M6 to
M2, where the coefficients for the first three size quintiles are relatively less
significant, suggests that CAPM cannot price relatively small portfolios well and that
there is more information in these portfolio returns related to size left unexplained by
CAPM than by C-CAPM discussed above. This inability to price small portfolios has
nothing to do with the book-to-market ratio. Moreover, as in M3, the coefficient on
the market return for the portfolios in the lowest book-to-market ratio in M7 is not
significant.
19
Table 5
Estimates of the CAPM
The table presents the estimates of the CAPM (M5-M8): 1960.2-2004.11, 538 observations. denotes
the market price of risk and i represents a coefficient for each conditional covariance in Equation 8.
t ( ) and t(i ) are their corresponding t–statistics respectively. The pricing models (M5-M8) are tested
against each other using the log-likelihood ratio test. 2log represents the likelihood ratio statistic. The
corresponding p-value at 5% significance level is denoted by p-value.
Panel A: 25 Size and Book-to-Market Portfolios
2.77
4s
t ( 4 s )
2 lo g
p va lu e
4b
t ( 4 b )
2 lo g
p va lu e
Size
Quintiles
Small
2
3
4
Big
Small
1.70
1.56
110.22
0.0000
Low
0.93
0.93
43.04
0.0020
Low
0.02
0.76
1.30
1.94
1.93
t ( )
Panel A1: Restricted CAPM (M5)
2 lo g
p va lu e
2.94
153.72
0.0000
Panel A2: Restricted Book-to-Market CAPM (M6)
Size Quintiles
2
3
4
Big
1.69
1.74
2.03
2.61
1.68
1.80
2.11
2.79
Panel A3: Restricted Size CAPM (M7)
Book-to-Market Quintiles
2
3
4
High
2.54
3.51
4.57
4.73
2.68
3.75
4.79
4.89
2
2.20
2.30
3.05
2.26
2.22
3
4 sb
3.02
3.55
3.14
3.59
2.70
Panel A4: Unrestricted CAPM (M8)
Book-to-Market Quintiles
4
High
Low
2
3
4
High
2.59
3.40
3.14
3.53
2.53
3.78
4.10
4.26
4.04
2.91
3.93
4.02
3.92
3.27
2.63
8
3.26
3.80
9
3.23
3.77
Large
2.45
2.88
8
6.96
7.97
9
6.18
6.86
High
6.24
7.04
t ( 4 sb )
4.37
4.36
4.37
4.16
3.20
4.51
4.34
4.26
3.57
3.21
0.02
0.67
1.15
1.74
1.81
1.75
2.16
3.00
2.26
2.15
Panel B: 10 Size Portfolios
4s
t ( 4 s )
Panel B1: Restricted CAPM (M5)
-0.47
t ( )
2 lo g
-0.34
811.30
Small
3.57
3.46
2
3.07
3.27
3
3.41
3.74
p va lu e
0.0000
Panel B2: Unrestricted CAPM (M8)
Size deciles
4
5
6
7
3.13
3.44
3.27
3.29
3.44
3.93
3.69
3.82
Panel C: 10 Book-to-market Portfolios
4b
t ( 4 b )
Panel C1: Restricted CAPM (M5)
1.98
t ( )
2 lo g
1.79
404.85
Low
3.14
3.19
2
4.29
4.73
3
4.68
5.39
p va lu e
0.0000
Panel C2: Unrestricted CAPM (M8)
Book-to-market Deciles
4
5
6
7
4.76
5.50
5.73
6.64
5.51
6.06
6.58
7.76
20
M5, M6, and M7 are rejected relative to the unrestricted model M8 based on their
likelihood ratio statistics of 153.72, 110.22, and 43.04 respectively. The likelihood
ratio statistics for CAPM are all larger than those for C-CAPM. As in C-CAPM,
allowing the coefficients on conditional covariances of market return with individual
excess return to be different offers extra information about the cross-section of the
equity returns. As can be seen from Figure 4, M8 can explain the variation in the cross
section well while M5 is not able to explain both size and value effects as in previous
studies (e.g. Fama and French , 1992 and 2006 and Lewellen and Nagel, 2006).
In M8, 20 coefficients on conditional covariances of returns with the market return,
including one for the market return (the coefficient on the variance), are more than 2
standard errors different from zero, while the other 3 coefficients are significant at the
10% significance level. The coefficients for the first 3 size and lowest book-to-market
quintiles are insignificant at any conventional level. These coefficients range from
0.02 to 4.51, exhibiting a clear positive relation with book-to-market ratio. However,
any relation between the coefficients and size can be seen only from the portfolios in
the last two book-to-market quintiles.
Figure 4
Cross-Sectional Fit: CAPM for the 25 Size and Book-to-Market Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 25 size and bookto-market portfolios. The estimated models are (a) M5, (b) M6, and (c) M7, and (d) M8. The average
excess returns are adjusted for the Jensen effect.
(b) Restricted Book-to-Market CAPM: M6
0.9
0.9
0.7
0.7
Predicted Risk Premium
Predicted Risk Premium
(a) Restricted CAPM: M5
0.5
0.3
0.1
-0.1
-0.1
0.5
0.3
0.1
0.1
0.3
0.5
0.7
-0.1
-0.1
0.9
Average Excess Return
0.1
0.3
0.5
Average Excess Return
21
0.7
0.9
(d) Unrestricted CAPM: M8
0.9
0.9
0.7
0.7
Predicted Risk Premium
Predicted Risk Premium
(c) Restricted Size CAPM: M7
0.5
0.3
0.1
-0.1
-0.1
0.5
0.3
0.1
0.1
0.3
0.5
0.7
-0.1
-0.1
0.9
Average Excess Return
0.1
0.3
0.5
0.7
0.9
Average Excess Return
M5 for the two sets of 10 portfolios does not perform well since the market
price of risk is of relatively low significance and in the case of the 10 size portfolios,
the market price of risk has the wrong sign. Therefore, the likelihood ratio test rejects
M5 for both 10 portfolios. M8 fits the data better than M5 (Figures 5 and 6), but its
coefficients exhibit a negative relation with size and a negative relation with book-tomarket ratio for both 10 portfolios as in the case of the 25 portfolios. On the other
hand, the relation between the consumption coefficients and firm characteristics in CCAPM can be seen only in the case of the 25 portfolios. Thus, C-CAPM can explain
size effect, but it has difficulty explaining the value effects; this exposure to the value
premium appears to be associated with both the book-to-market ratio and, to some
extent, with size.
22
Figure 5
Cross-Sectional Fit: CAPM for the 10 Size Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 10 size portfolios.
The estimated models are (a) M5 and (b) M8. The average excess returns are adjusted for the Jensen
effect.
(b) Unrestricted CAPM: M8
1.0
1.0
0.8
0.8
Predicted Risk Premium
Predicted Risk Premium
(a) Restricted CAPM: M5
0.6
0.4
0.2
0.0
-0.2
-0.2
0.6
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
-0.2
-0.2
1.0
0.0
0.2
Average Excess Return
0.4
0.6
0.8
1.0
Average Excess Return
Figure 6
Cross-Sectional Fit: CAPM for the 10 Book-to-Market Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 10 book-tomarket ratio portfolios. The estimated models are (a) M5 and (b) M8. The average excess returns are
adjusted for the Jensen effect.
(a) Restricted CAPM: M5
1.3
1.1
Predicted Risk Premium
Predicted Risk Premium
1.1
0.9
0.7
0.5
0.3
0.3
(b) Unrestricted CAPM: M8
1.3
0.9
0.7
0.5
0.5
0.7
0.9
1.1
0.3
0.3
1.3
Average Excess Return
0.5
0.7
0.9
1.1
1.3
Average Excess Return
5.2.3 C-CAPM and CAPM
We further investigate the ability of C-CAPM (M1) and CAPM (M4) by comparing
the behavior of the conditional covariances in both models, as given in Table 6 below,
with the average excess returns of the 25 portfolios shown in Table 2. The
23
consumption covariance obtained from the estimation of C-CAPM decreases, as we
move down the column, indicating a negative relation with size. Thus, C-CAPM can
capture the size effect. However, in the lowest book-to-market quintiles, average
excess returns increase as the size of the portfolios grows larger. This result is
consistent with the results in Table 4 where the coefficients for these portfolios in M3
and M4 are not significant from zero.
Table 6
Conditional Covariances of the Returns on the 25 Portfolios in M1 and M5
The table shows the average conditional covariances of the returns with consumption and market
returns as implied by the C-CAPM and CAPM, respectively. Each conditional covariance is given in
percent per month and estimated by the multivariate GARCH in the mean.
Book-to-market ratio Quintile
Size
Quintile
Small
2
3
4
Big
Small
2
3
4
Big
Low
2
3
4
High
Panel A: Conditional covariance of consumption
0.32218
0.28800
0.31130
0.22016
0.27699
0.24066
0.23827
0.23237
0.17594
0.20899
0.19671
0.17586
0.16247
0.15597
0.17918
-0.00131
-0.00166
-0.00138
0.00593
0.00496
0.00304
0.00001
-0.00133
-0.00127
-0.00040
Panel B: Conditional covariance of market return
0.32143
0.35714
0.25829
0.25272
0.28785
0.24282
0.22963
0.21088
0.24303
0.17777
0.23056
0.18894
0.18875
0.17934
0.16103
0.18551
0.21742
0.20223
0.15693
0.20226
0.27074
0.24804
0.19669
0.16809
0.16478
C-CAPM appears to miss the value premium completely by not producing
dispersion in the consumption covariance across the book-to-market quintiles. In fact,
the consumption covariances for the 5 portfolios in the highest book-to-market
quintile seem to be slightly lower than those in the lowest book-to-market quintiles,
indicating lower risk premium is implied by C-CAPM. On the other hand, the
condition covariances of the returns with the market returns in CAPM, in addition to
having a similar behavior across book-to-market quintiles as consumption covariances,
appear not to be able to capture the size effect as well. The dispersion of the market
covariances is not big enough to explain the differences in the excess returns across
size, confirming our previous results where the coefficients for the first two size
quintiles in M6 were not highly significant.
24
We add a constant term in M1-M8 for the estimation of the 25 portfolios to
measure variation in excess returns that was left unexplained in each model. In
general, we expect the constant term in C-CAPM to be of more significance than in
those in CAPM because pricing asset returns with market return is expected to be
more precise than using aggregate consumption data. However, Table 7 shows that for
the magnitude of the constant terms in CAPM, 1.98 is larger than that for C-CAPM at
0.86. This larger magnitude of CAPM is present in every restricted version. The
magnitude of the constant is also larger than in Fama and French (1993) with a
constant for the CAPM being 0.04 to 0.57 (in absolute terms).
Table 7
Constant term
The table presents the estimates for the constant term, in all versions of the C-CAPM and CAPM, M1M8 in Table 1, for the 25 portfolios formed based on size and book-to-market ratio. The number in the
parentless is the t-statistic associated with each constant term.
Constant
Constant
M1
0.84
(5.36)
M5
1.98
(9.13)
Panel A: C-CAPM
M2
1.14
(6.39)
Panel B: CAPM
M6
1.75
(6.79)
M3
0.52
(2.75)
M4
0.87
(1.75)
M7
0.56
(1.85)
M8
0.94
(1.70)
The information about the cross-section of equity returns left unexplained in
C-CAPM seems to be less than that in the CAPM. Moving from M1 to M4 decreases
the significance of the constant terms (except for moving from M1 to M2), suggesting
that allowing coefficients of conditional covariances within the same book-to-market
ratio to be different is more important than allowing the coefficients to be different
across size quintiles; the magnitude and level of significance of the constant terms
reduces more when moving from M2 to M3 than when moving from M1 to M2. This
argument is also true for CAPM when moving from M5 to M8.
5.2.4 General SDF Models
Table 8 reports the estimates of the general two- and three-factor SDF models based
on consumption, inflation, and industrial production. We are unable to estimate M10
and M12 for the 25 portfolios due to the high parameterization of the MGM. As in
Smith, Sorensen, and Wickens (2008), we find that industrial production plays no role
25
in evaluating asset returns, but inflation is significant. The coefficient on the
conditional covariance of inflation for the 10 book-to-market portfolios is positive
because the contribution to the risk premium by consumption is higher than it is for
actual excess return. The estimation of M9 and M11 for both 10 portfolios shows that
the restrictions they provide on M10 and M12 cannot be rejected by the likelihood
ratio test, implying that the coefficients for conditional covariance of consumption
and inflation with the returns are similar across size and book-to-market deciles.
However, M9 does not explain the data better than C-CAPM and the CAPM (Figure
7).
Table 8
Estimates for Restricted Macro SDF Models
The table presents the estimates for the restricted general SDF models (M9 and M11): 1960.2-2004.11,
538 observations. i represents a coefficient for each conditional covariance in Equation 8. t(i ) is its
corresponding t–statistics respectively. The pricing models (M9 and M11) are tested against their
respective unrestricted alternatives (M10 and M12) using the log-likelihood ratio test. 2log represents
the likelihood ratio statistic. The corresponding p-value at 5% significance level is denoted by p-value.
Model
M9
M11
M9
M11
M9
M11
1
2
3
Panel A: 25 Size and Book-to-Market Portfolios
72.93
-115.72
(3.40)
(-1.74)
72.82
-116.47
1.42
(3.40)
(-1.73)
(0.06)
Panel B: 10 size portfolios
59.29
-130.87
(2.18)
(-2.01)
59.62
-137.76
16.84
(2.17)
(-2.08)
(0.55)
Panel C: 10 Book-to-market portfolios
307.12
147.29
(8.00)
(1.92)
305.17
141.17
8.58
(7.87)
(1.82)
(0.35)
26
2 lo g
p va lu e
23.66
0.1666
33.43
0.1832
23.27
0.1805
32.33
0.2201
Figure 7
Cross-Sectional Fit: Two-Factor SDF Model for the 25 Portfolios
The figure plots average actual versus predicted excess returns (% per month) for the 25 size and bookto-market ratio portfolios. The estimated model is M9. The average excess returns are adjusted for the
Jensen effect.
M9: Restricted Two-Factor SDF Model
1.4
1.2
Predicted Risk Premium
1.0
0.8
0.6
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Average Excess Return
6. Conclusion
This paper examines the behavior of the cross-section of equity returns based on the
no-arbitrage condition derived from the Stochastic Discount Factor approach to asset
pricing. We test whether the conditional covariances of the equity returns across
portfolios formed on size and book-to-market ratio with discount factors in each asset
pricing model can sufficiently explain the excess returns in these portfolios. Our
results indicate that the no-arbitrage test rejects C-CAPM as the model can explain the
size effects, but not the value effect. Although the consumption covariances exhibit a
negative relation with size, but they do not vary with the book-to-market ratio. This
behavior explains why the likelihood ratio test indicates that the coefficients for the
consumption covariances are not similar across book-to-market ratios.
Allowing the coefficients on the conditional covariances with consumption to be
different across portfolios generally improves the fit of C-CAPM. Even without
adding any factor to the model, the performance of the resulting unrestricted CCAPM is comparable to the modified version of C-CAPM of Lettau and Ludvigson
(2001), Parker and Julliard (2005), Yogo (2006) and Savov (2011). The unexplained
variation in excess returns is less than for unrestricted C-CAPM as the significance of
the constant term is lower than that in standard C-CAPM. Unrestricted C-CAPM does
27
not explain the small growth portfolios well, but this phenomenon is common to most
asset pricing models.
Our results confirm the findings of Abhakorn, Smith, and Wickens (2013) that
both firm size and the book-to-market ratio need to be included in the model in order
discover a value effect. Firm size or the book-to-market ratio on their own does not
generate information about average returns that improves on C-CAPM. This requires
the double sorting of stocks according to size and the book-to-market ratio for the 25
Fama-French portfolios. This finding suggests that there is an additional dimension of
risk left unexplained by C-CAPM or by an SDF model with only one of these factors .
This extra dimension of risk seems to be associated with both (small) size and a (low)
book-to-market ratio. A possible explanation for this extra dimension of risk is the
investment growth prospect of firms, see Abhakorn, Smith, and Wickens (2013), and
could be the reason that the investment-based asset pricing models of Brennan, Wang,
and Xia (2004) and Li, Vassalou, and Xing (2006) are able to explain the crosssection of equity returns.
Our results
indicate that C-CAPM with size and the book-to-market ratio as
additional factors contains information about cross-section average returns that is not
captured by CAPM in previous studies by, for example, Fama and French (1992 and
2006) and Lewellen and Nagel (2006). In general, SDF models suggest that inflation
seems to be significant in determining stock returns, but industrial production plays
no role in determining stock returns. However, pricing models that include inflation
do not perform better than C-CAPM.
28
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