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Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
TITLE: PORTFOLIO SELECTION REVISITED: EVIDENCE FROM THE
INDIAN STOCK MARKET
Authors’ Affiliation
First Author: Shri Kushankur Dey
Doctoral Student, 3rd Year
Fellow Programme in Rural Management
Institute of Rural Management, Anand (IRMA)
Gujarat-388001
Email: [email protected] / [email protected]
Second Author: Shri Debasish Maitra
Doctoral Student, 2nd Year
Fellow Programme in Rural Management
Institute of Rural Management, Anand (IRMA)
Gujarat-388001
Email: [email protected] / [email protected]
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
ABSTRACT
Investment theory in securities markets pre-empts the study of the relationship between risk and
returns. In this parlance, the behavior of stock-price (movement) has been a recurrent topic in
financial jargon. A large number of studies have reported the risk-return equation of the group of
assets or the portfolios. A couple of literature have been carrying the magnitude of the results with
respect to the portfolio selection, evaluation and optimisation since a long time-period. Several
models are also being proposed and reviewed in view of their utilities and validities with renewed
interests of the diverse participants. Hence, this paper is an attempt to examine the reliability and
usefulness of the ex-ante measures for formulating the portfolio in a congruent manner.
Prima facie the Sharpe single-index model is incorporated in the study, besides, the Treynor-index, the
Jensen-index, and the Sortino-index, which of course, have yielded relatively a superior and legitimate
result as compared to a single-index model or measure. The study is conducted in Indian context
with special reference to S&P CNX NIFTY index. NIFTY is considered as a proxy of the market,
that comprises of 50 individual stocks and incorporation of these stocks are subject to three criteria;
liquidity, market capitalisation, and floating stocks. Using the Sharpe postulated “algorithm”, cut-off
is calculated to select and formulate the portfolio. 26 stocks have qualified to form the portfolio. A
comprehensive analysis of each individual stock, portfolio, and the index is carried out with respect
to their annualised returns, annualised standard deviations, betas, residual variances or deviations
using the mentioned ratios. Mean-variance efficient portfolio is graphically presented in the paper
adopting the Markowitz’ risk-return measures approach.
Therefore, this paper is an amalgamation of both the modern- and post-modern portfolio theory
with a logical and an elegant approach. Moreover, this study, evidently, provides a basis to a large
section of investors, especially retail investors for analysing, selecting, and evaluating the portfolio as
a mirror image of the index on a specific reference point of his/her portfolios in order to achieve
the optimisation of assets allocation and risk-restructuring in the Indian context.
Keywords: Portfolio theory, post-modern portfolio theory, Sharpe-ratio or index, Treynor-ratio,
Jensen-ratio, Sortino-ratio, Coherent measures of risk
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
1. MOTIVATION
With the advent of information technology, there have been significant changes
observed in the landscape of stock markets worldwide. Obviously, Indian stock market
is not an exception to the effect of globalization. Besides the relay-race of a band of
qualified institutional buyers (QIBs) and non-institutional buyers (NIBs) in the market,
evidently, small or retail investors are also taking interest to invest now-a-days.
Moreover, they understand and play the game by virtue of the “buy-low and sell-high”
strategy. Often this type of investor falls into a trap by showing “herd” behaviour or
sometimes reaps a quantum of “momentum-profit” by adopting “contrarian” strategy.
A good mix of fundamental and technical analysis helps the investor to formulate the
strategy either for buying or for selling the stocks or securities. This is, in a true sense,
called portfolio selection and evaluation. On apriori basis, if investor seems to have a set
of full-information about the market, he/she can invest proportionately to make a
relative gain. Once the investor experiences his/her gain (loss) without knowing or
predicting the market, he or she further does investment while taking the lessons from
the past. We try to make it clear that individual or personal finance influenced by
individual’s mental accounting, representativeness in the market (law of small
numbers), disposition effect, conservatism, overconfidence, etc.;-which have
undoubtedly taken a distinct place in the realms of “behavioural finance”. We depart
from this, rather we take our position to explore and explain adopting the philosophy of
positive economics behind the occurrence of gain or loss of the investor. It is of course, a
branch of financial economics, called security analysis and portfolio management (part
of modern portfolio theory). There were many contributions already made enrichment
of this field till late eighties. Hence, an attempt has been made to analyse the use of
security to improve the portfolio selection adopting the single-index (algorithmic)
model of William Sharpe (1964) in this paper along with a tinge of other approaches of
post-modern portfolio theory, say, Sortino ratio or index.
In first section, introduction is narrated succinctly; section-two looks at literature review
followed by objectives, hypotheses, and methodology in section-three. Section-four
discusses the results and findings. Section-five summarises the whole paper and comes
out with implication or leaves few signposts for the future research.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
SECTION-I
2. INTRODUCTION
Relationship between return and risk has been receiving significant importance in
realising the optimal allocation of stocks or optimal investment strategy or even for
testing the market anomalies for abnormal stock returns in a horizon of time-period
(Nath and Dalvi 2004). Hence, portfolio analysis has remained one of the highly
pursued areas of research in financial economics for more than three decades. More
implicitly, this makes a choice to the investor to take a wise action or prudent inaction
which, in turn, compels the investor to cogitate upon the risk-return embedded
relationship of the asset. In real world, we try to measure the standard deviation as a
proxy or surrogate to risk and investor attitudes toward portfolios depend exclusively
upon expected return and risk (Markowitz 1959). Since diversified portfolios reduce the
occurrence of unsystematic risk, avoidance of systematic one is of huge challenge to the
investor. As noted that the variance of returns on an asset is a measure of its total risk
and variance can be split into systematic and unsystematic risk, that is, 2i = β22m + 2εi,
where β is systematic factor, 2m denotes the systematic risk and 2εi is unsystematic
risk contained portfolio. Thus, it would be relevant to measure the correlation or
covariances (rx,y or Covx,y) of the two or more stocks to the ratio of their individual
standard deviation (σx, σy and σi). This raises serious concerns to the investor that how
much investment is required in each stock to formulate an optimal portfolio.
At this juncture, we try to bring some classics in the context of modern portfolio theory,
which is obviously recounted with few barons of financial economics, namely, Roy,
Markowitz, William Sharpe, Treynor, Black, Jensen, and Sortino. Markowitz in his
noble winning paper arguably stated that the process of selecting a portfolio may be
divided into two stages. The first stage starts with observation, experience, and ends up
with beliefs about the future performances of available securities. The second stage
starts with the relevant beliefs about future performances and ends with the choice and
selection of portfolio (Markowitz 1952). This actually gave a birth to the modern
portfolio theory in positive economics. Markowitz is also clear that historical data does
not matter rather beliefs about the future as intuitively he posited that historical data is
of interest only in so far as it helps form those beliefs about the future. Since different
people have different beliefs, Markowitz’s pathbreaking research gives a motivation to
investors to formulate a portfolio that can serve a proxy for the market in true sense.
More so, he is not bothered about how those choices affect equilibrium process in the
market. Sharpe (1964) assumed that investors are homogeneous in nature and are
expected to agree on the expected returns, standard deviations and correlations of the
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
securities or stocks in chosen portfolio. Following the legendary works of others, two
questions are relevant to pose at this juncture; (i) what would be the security return as a
result of the event occurred in the economy or stock market in some point in time,
which might be unexpected, or (ii) what would be the market return as a result of that
particular event?
SECTION-II
3. LITERATURE REVIEW
Going by the definition of market efficiency which denotes that a market is efficient
with respect to make abnormal returns or profits (other than by an incidence or by
chance) by using this set of information to formulate buying and selling decisions
(Bharadwaj 2009). We look at two types of popular analyses; one is “fundamental” and
the other “technical”. These two have their own significant impact on investor’s
decision making (DM) with respect to self-financing portfolio or zero-investment
(arbitrage) portfolio. Precisely, fundamental analysis takes into accounts of
macroeconomic indicators, industry benchmark ratio and company whereas technical is
based on charting and trend analysis, say, breadth analysis (dispersion of price-volume
ratio), relative-strength-indicator, moving average convergence-divergence (MACD)
and Elliot’s wave study and band (Bollinger) analysis, etc. There are many tools and
techniques already evolved to make the payoff or loss more certain without a mere and
naïve investment strategy. On the corollary, it is obvious that market follows its own
pattern satisfying the random walk hypothesis (RWH) or Chartists’ theory. Hence, we can
say that “the behaviour of stock price has been a recurrent topic in financial jargon.
Stock price is time varying and depends upon its past information, market news, and
various macroeconomic factors*” (Pradhan 2009: 1). French and Roll (1986) empirically
showed that flow of information affects the magnitude of trading time following the
observations and impacts on volatility, which follows trading time hypothesis (French and
Rogalski 1980) rather than calendar time hypothesis. Hence, there is a trend-reversal
observed following the “formation” (say 6 months) and “test” (say, rest 6 months)
period in post-event phenomena. This seems to have a formation of “conformity bias”
as a difference between winner’ and looser’ portfolio (W-L) as pointed out by Jagdish
and Titman (1986). On the other side, there is an impact of value of assets and growth *Adapted from the paper, “Stock Price and Macroeconomic Indicators in India: Evidence from
Causality and Cointegration Analysis” by Rudra P. Pradhan, Vinod Gupta School of Management, Indian Institute of Technology Kharagpur. This paper was presented at the conference, “Advanced Data Analysis, Business Analytics and Intelligence”, Indian Institute of Management-Ahmedabad, 2009.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
on stock return. Cooper (2009) suggested that stocks with higher assets growth usually
underperform relative to those with lower assets growth. Hence, it is advisable to take a
long (buy or bid) position of stocks with higher return on assets (ROA) and a short (sell
or ask) position of stocks with relatively lower ROA or assets growth. Hvidkjaer (2005)
discussed the role of (extrapolation bias) small traders in the market showing the trade-
based analysis of momentum through the cross-sectional analysis of stock returns.
Factors determining this momentum profit or variances in the stock returns with a
sentiment period in trading are namely, one month across return (negative), trading
volume/market capitalisation (negative), earnings-to-price (positive), return on equity
(positive), book-to-price (positive),etc. Here, momentum is the effect that reasons out
that winner tends to “win” and losers tend to “loose” for three to six-months horizon or
reference frame of wealth allocation. This explanation draws argument from the realms
of behavioural finance. Now-a-days, algorithmic studies are conducting in this branch
which is akin to positive financial economics.
Against this backdrop, simplified, logical, and elegant or a single-index model helps to
measure the capital-asset pricing. Theoretically, we can say that capital market theory is
a major extension of the portfolio theory of Markowitz (Sharpe, 1964). Portfolio theory is
really a connotation of how rational investors should build efficient portfolios or
frontiers. On the other hand, capital market theory pre-empts us how assets should be
priced in the capital markets if, indeed, everyone behaved in the way portfolio theory
suggests. So the capital asset pricing model (CAPM) is a relationship amplifying how
assets should be priced in the capital market (Fama and French 2004). The model
simplifies the complexity of real world, tells us that a linear relationship exists between
a security’s (stock) required rate of return and its beta as investment theory suggests
that beta is an approximate measure of risk for portfolios of securities that have been
sufficiently diversified (Singh, 2008). Historically calculated beta and risk premium (Rm-
Rf) used to determine the required rate of return (Ri, or expressed as Ri=Rf +β(Rm-Rf) or
Ri=+bβ +εi) on the investor’s portfolio. The question is on whether we adopt the ex-
ante or ex-post measures of beta to arrive at realistic return of the investor. This holds
true for a hemophilic group of people containing same belief.
Treynor and Black (1973) showed empirically that adequate usage of security analysis
can help to improve portfolio selection and they interpreted CAPM as putting forward
that the investor should hold a model or replica of the market portfolio as investors
have different expectations from the market consensus because of the absence of insight
generating information. This implicitly tells about that the market is “noisy” and the
assumption of Efficient Market Hypothesis (EMH) does not hold true in all cases
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
(Grossman and Stiglitz 1980; Fama 1991; Nelson and Schertz 1996; Campbell, Lo and
MacKinlay 1997). Very often, semi-strong (containing historical and public information)
form of the market seems to persist. Following the elegant model of Treynor and Black
on “portfolio choice” while investors had out of consensus beliefs, assumptions
underlying EMH connotes that individual investor who is attempting to trade
profitably on the difference between her expectations and those of a monolithic or
gigantic market so large in relation to her own trading activities or strategies that
market prices are unaffected by it (Varma 2010). Similar ideas can be traced in the
popular Black-Litterman model of “Global Portfolio Optimisation” (1992) which started
with some postulations, namely, we ready to accept that there are two distinct sources
of information about future excess returns;- investor views and market equilibrium; we
assume that both sources of information are uncertain and are best expressed as
occurrence of probability or distributions; lastly, we choose expected excess returns that
are as consistent as possibly with both sources of information.
Even we stick to the market consensus, the CAPM beta itself has to be interpreted with care. The deviation of the CAPM makes it clear that the beta is actually the ratio of covariance of security’s return and market return to a variance of the market return and both of these are parameters of the subjective probability distribution that defines the market consensus…this may be formally correct, but it is misleading because it suggests that the beta is defined in terms of a regression on past data (Varma2010: retrieved from www.iimahd.ernet.in/~jrvarma/blog/index.cg on May 5, 2010).
Beta is considered as regressor (excess return of market portfolio on excess return of
individual stock). But the conceptual meaning of beta is somehow different as empirical
work of Guy and Rosenberg (1976) established in their paper, “prediction of beta from
investment fundamentals” by incorporating few industry estimates, viz., variance in
earnings, variance in cash flows, debt-to-equity ratio (levered or unlevered firm), debt-
to-asset ratio, etc. Hence, there should be subjective beliefs about possible yet uncertain
future changes in the beta because of changing business strategy or financial strategy
must also be considered. The underpinning of this can serve purposes of an investor,
assuming a rational one in positive economics, seems to be agreeable at several
occasions that market is random and it has long-indefinite memory to reach equilibrium
or may show a mean-reverting process or simply white noise after removing trend or
drift. Therefore, it is quite intuitive that the data generating process does not remain
same for too long being coupled with a proper method or fundamental judgment to
reduce the sampling error. Being a rational investor wants to optimise the return and
risk theoretically that gives a “mean-variance efficient portfolio frontier” underlying
some feasible regions.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Fortunately, Markowitz’s propositions about the efficient frontier that postulates two
relevant parameters of the frequency distributions or two moments which are, namely,
mean (first moment) and variance (second). He further stated that formulation of
portfolio does not require any further higher-order parameters (Markowitz 1952; Ghosh
2009). Added that the covariance feature is most important that promotes the advantage
through diversification of assets in the portfolio. This actually minimises the probability
of occurrence of unsystematic risk to a certain limit. This criterion is applicable for more
than 2-security’s (NC2) portfolio. If securities are two, there is no advantage from
diversification if rates of return from those securities are positively and perfectly
correlated (rx,y =+1) which is unlikely happened with perfectly, negatively correlated
security’s portfolio (rx,y =-1). In this case, portfolio return would be achieved with
certainty. On the other side, the lower the magnitude of correlation, the better it is for
diversification, and the negative value, if it is to be ascertained for correlation, is most
desirable. Hence, there is a relation of inequality between the correlation coefficient and
the ratio of 2-security’s standard deviations would score good to delineate cases of
advantage from diversification to those which are not. Markowitz’ work was precisely a
post-hoc work that was mostly concentrated on a small set of securities. Sharpe’s
algorithm (1963 and 1964) tried to overcome the actual problem of formulating efficient
portfolio in reality (stock market) and he had come out with a predictive, ex-ante model
to establish the generalisation of modern portfolio theory covering a large set of
securities or the universe in the gamut of financial economics. His single-index model
brought an approach to the covariance of the stock prices that has been to identify the
underlying economic forces simultaneously affecting all the stocks in the market.
Hence, a shift from microeconomic bias to macroeconomic one was taken place
gradually. This single-index model is nothing but a forecast of the market rate of return
and also of its variance during the holding period, in addition the expected rate of
return and the variance for each security or stock in the starting selection vector of those
stocks.
The distinction between Markowitz’ model and Sharpe’s model was that the former
model was based on historical data that underscored the merit to attempt to foresee or
forecast a relevant parameters or value in the future, involving the holding period for
the fund relation or investment. The latter model specifically brought in the expected
future values of the market return and in variance and these are essential elements
determining the various parts of the optimisation or optimally calculations. Sharpe ratio
or index (excess return from risk-free rate of return to standard deviation of return of
portfolio) helps to identify the “reward-to-variability” of the investor’s portfolio.
Treynor ratio or index (excess return from risk-free rate of return to beta of portfolio)
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
and Jensen performance-measures (difference between investor’s excess return and
market return as a proxy for alpha coefficient) contributed substantially to the modern
portfolio theory.
After 1990s, few observations were noticed and documented by financial experts, viz.,
Sortino (1991) in view of asymmetric distributions of stock values and random
cashflow. This situation compelled to incorporate several model-building approaches,
namely, mean-risk model, expected utility maximisation, and stochastic dominance to
capture the randomness of the stock-return precisely. These phenomena gave a rebirth
or transformation of modern portfolio theory to post-modern portfolio theory (PMPT). Sortino
index (excess return from risk-free rate of return to down-side risk) came into being for
allocating assets or securities to capture the asymmetric distribution of stock return.
Sortino and Price (1994), and Pederson and Satchell (2002) proved that the risk-return
frontier while risk is defined by stochastic second-order dominance (SSD-II), exhibits
the same expected convexity properties of the traditional mean-variance frontier, thus,
is desirable for portfolio analytics. Sortino index is defined as:
As an alternative, the Sortino ratio has been advocated in order to capture the asymmetry of the return distribution. It replaces the standard deviation in the Sharpe ratio by the downside deviation which captures only the downside risk. However, higher moments are incorporated only implicitly (Bacmann and Scholz, see also, Sortino 1998; http://www.sortino.com/htm/Sortino%20Ratio.htm.)
Therefore, the Sortino ratio is akin to the Sharpe ratio except that the square root of the
semi-variance replaces the volatility or it connotes that the risk is only measured with
down-moves that is, relative to some target value or minimum acceptable returns
(MAR). Lien (2002) argued that excessive kurtosis (fourth moment) has hardly any
impact on the monotonic relation between Sortino and Sharpe ratios. Considering
portfolio returns are normally distributed (log-normal), it is obvious that both Sortino
ratio (SR) and upside potential ratio (UPR) are monotonically increasing functions of
the Sharpe ratio. Hence, these three risk-measures provide an extent for identical
ranking of portfolio alternatives. Plantinga and de Groot (2001) stated that for higher
levels of loss or risk-aversion, the Sortino ratio succumbs to the best results with a
correlation of approximately 60% with the preference function. Still, Sortino ratio has
attracted few critics from the point of coherent risk measures as this ratio or “value at
risk” (VaR) are ad-hoc attempts to measure the downside risk whereas there is potential
ignorance of incorporating upside risk-measures (Leland 1998). Hence, both are
“generally inaccurate as an appropriate risk and/or performance measures” (Leland
1998).
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
SECTION-III
4. OBJECTIVES
Based on the literature review, we try to formulate a portfolio using the database of
Indian capital market, which is the constituent of stock and bond market precisely.
i. Use of Sharpe-single index model and ratio-analysis (Treynor, Jensen and
Sortino) to formulate and improve the portfolio selection are to be ascertained
through adequate employment of stocks returns- and market returns-series of
the S&P CNX NIFTY index.
ii. Performance of portfolio is to be evaluated with respect to index by setting few
relevant parameters, namely, beta, market return, stock return, systematic risk,
unsystematic risk, and downside risk.
Cross-sectional analysis is incorporated to administer the revenant tests in order to
arrive at the stated objectives.
5. HYPOTHESES
H1: Mean-variance efficient portfolio is likely to be achieved by incorporating Sharpe
single-index model approach as an ex-ante measure of the modern portfolio theory in
Indian context.
H2: Portfolio risk-return optimisation scores relatively higher than the index or market
risk and return equation.
H3: Optimal portfolio selection is possible using the Sharpe single-index model if and
only market is considered a proper vector space.
H4: A good combination of all ratios would define the portfolio relatively superior to a
single-ratio based approach as a contingency approach and corroborate to the
principles-based coherent risk measures and post-modern portfolio theory.
Negations of the above mentioned alternate hypotheses are nothing but the null ones
(hypotheses).
6. METHODOLOGY
Methodological purposiveness and congruence are two most critical issues in financial
economics. Concordance about the model selection should be achieved to empirically
test the chosen statistical model in order to arrive at precision and to approximate the
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
reality (ontology). Model is a representative of the theory which tries to explain any
phenomena comprehensively and consistently. In this section, we try to define the
model and to delineate the set of procedures for the measurement.
6.1. Model Specifications and Notations
We consider that let there be N risky assets with mean vector μ and covariance matrix Ω
assuming that expected return from at least two assets differ and their covariance
matrix is of full rank (linearly independent or orthogonal in nature). Define ωa as the (N
X 1) vector of portfolio weights for an arbitrary portfolio “a” with weights summing to
unity (1). Portfolio “a” has mean return μa = ωa’ μ and variance, σ2a = ωa’ Ω ωa. The
covariance between any two portfolios “a” and “b” is ωa’ Ω ωb. Given the population of
assets, minimum-variance portfolios are constructed in the absence and presence of
risk-free asset (Merton 1972; Roll 1977; Campbell, Lo, and Mackinlay 2007).
Stylized Fact: Portfolio p is the minimum-variance portfolio of all portfolios with mean return
μp if its portfolio weight vector is the solution to the following constrained optimisation:
min ω’ Ω ω (i)
ω
subject to
ω’ μ = μp (ii)
ω’τ = 1 (iii)
To solve the optimisation problem, we formulate the Lagrangian function L,
differentiate with respect to ω, set the resulting equation to zero, and then solve for ω.
To arrive at stable solution, the Lagrangian function we have
L = ω’ Ω ω + δ1 (μp- ω’ μ) + δ2 (1- ω’τ) (iv)
Where τ is a conforming vector of ones and δ1 and δ2 are Lagrangian multipliers.
Differentiating L with respect to ω and setting the result equal to zero, we get
2 Ω ω - δ1 μ - δ2 τ = 0 (v)
Combining (v), (ii), and (iii) equations, we find the solution
ωp = g + hμp (vi)
Where g and h are (N X 1) vectors, g = 1/D [B (Ω-1 τ) – A (Ω-1 μ)] (vii)
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
h = 1/D [C (Ω-1 μ) – A (Ω-1 τ)] (viii)
and A = τ’ Ω-1 μ, B = μ’Ω-1 μ, C = τ’ Ω-1 τ, D = BC- A2
For example, p and r are two minimum-variance portfolios. The covariance of the return
of p with the return of r is
Cov (Rp, Rr) = C/D (μp –A/C) (μr –A/C) +1/C (ix)
And portfolio g as the global minimum-variance portfolio and for each minimum-
variance portfolio, say p, except the global one, there exists a unique minimum-variance
portfolio that has zero covariance with p. This portfolio is said to be the zero-beta
portfolio with respect to p. Hence, we have
ωg= 1/C Ω-1 τ, μg= A/C, σ2g = 1/C (x)
Cov (Rg, Rp) = 1/C (xi)
We now introduce a risk-free asset into the analysis and consider portfolios composed
of a combination of the N risky assets and the risk-free asset. With a risk-free asset the
portfolio weights of the risky assets are not constrained to sum to unity, since (1- ω’τ)
can be invested in the risk-free asset. Therefore, given a risk-free asset with return Rf the
minimum-variance portfolio with expected return μp will be the solution to the
constrained optimisation.
min ω’ Ω ω (xi)
ω
subject to ω’ μ+ (1- ω’τ) = μp (xii)
Taking the Lagrangian function L, differentiate it with respect to ω, set the resulting
equation to zero, and then solve for ω. Hence, we have
L = ω’ Ω ω+ δ μp- ω’ μ-(1- ω’τ) Rf (xiii)
Differentiating L with respect to ω and setting the result equal to zero, we get
2 Ω ω+ δ (μ-Rf τ) = 0 (xiv)
Combining (xiv) and (xii) equations, we get the solution,
ωp = (μp - Rf) / (μ-Rf τ)’ Ω-1(μ-Rf τ)* Ω-1(μ-Rf τ) (xv)
We can express ωp as a scalar which depends on the mean of p times a portfolio weight
vector which does not depend on p in the given vector space.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
ωp = cpŵ where cp = (μp - Rf) / (μ-Rf τ)’ Ω-1(μ-Rf τ) and ŵ = Ω-1(μ-Rf τ) (xvi)
Thus with a risk-free asset all minimum-variance portfolios are a combination of a given
risky asset portfolio with weights proportional to ŵ and the risk-free asset. This
portfolio of risky assets is said to be the tangency portfolio and has a weight vector.
Therefore, with the help of portfolio weight vector, tangency portfolio is construed and
with a risk-free asset all efficient portfolios lie along the line from the risk free asset
through portfolio q. Hence, we get
ωq =1/ τ’Ω-1(μ-Rf τ)* Ω-1(μ-Rf τ) (xvii)
The expected excess return per unit risk is useful to provide a basis for economic
interpretation of tests of the CAPM. This can be achieved using the Sharpe ratio. For any
asset or portfolio “a”, the ratio is defined as the mean excess return (Ri–Rf or μa –Rf)
divided by the standard deviation of return of assets or portfolio.
Sra = (μa –Rf )/σa (xviii)
Treynor index is slightly different from the Sharpe ratio. It is defined as the mean excess
return (Ri–Rf or μa –Rf) divided by the beta of assets or portfolio.
Tra = (μa –Rf )/βa (xix)
Jensen performance-measures approach provides a basis for calculating alpha ()
coefficient or intercept of the portfolio. Hence, we can get from the CAPM (two-factor)
model
(μa –Rf) = +βa (μm - Rf), or Jensen measures, = [(μa –Rf) - βa (μm - Rf)] (xx)
Sortino index is defined as the mean excess return (Ri–Rf or μa –Rf) divided by the
downside risk or asymmetric distribution of stock or portfolio return.
Sora = (μa –Rf )/da (xxi)
In analysis, we have used the mentioned ratios. Sharpe-Linter version of the CAPM is
drawn from market-model building approaches which we have used for calculating
beta as regressor and residual variance or unsystematic risk on daily-count basis of the
index. Define Zt as an (N X 1) vector of excess returns for N assets or portfolios of assets,
for these N assets; the excess returns can be described using the excess-return market
model:
Zt = +βZmt +Єt, where E[Єt] = 0, E [Єt, Єt’] = ∑, E [Zmt] = μm, E [(Zmt - μm) 2] = σ2m,
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Cov [Zmt, Єt] = 0 (xxii)
β is the (N X 1) vector of betas, Zmt is the time period t market portfolio excess return,
and and Єt are (N X 1) vectors of asset return intercepts and disturbance or noise,
respectively. In case of Sharpe single-index model, the algorithm involves the following
equations presented in the table below:
Table 1: William Sharpe Single-index model-notation
Rank-
order
(1)
Security
No.
(2)
Excess
mean
return
(3)
Excess
mean
return
to beta
(4)
Excess
return
times beta
to residual
variance
(5)
Beta to
Residual
variance
(6)
Cum.
(5)
Cum.
(6)
Cut-off
or C*
(7)
Z-value
or
Optimal
portfolio
selection
(8)
1, 2,
3…
a1, a2, a3… (μa –Rf ) (μa –Rf
)/βa
(μa –Rf )
βa/σa2
βa/σa2 ∑(μa
–Rf )
βa/σa2
∑
βa/σa2
[σ2m∑(μa
–Rf )
βa/σa2]/
[1+
σ2m(∑
βa/σa2]
βa/σa2((μa
–Rf )/βa -
C*)
Note: Security’s selection to formulate portfolio is based on benchmark ratio or cut-off score. Securities which have
higher excess mean return to beta to calculated cut-off score, those would be eligible to enter into the portfolio. Z-
value would decide the proportion or weights of stocks or securities in the portfolio and based on this, ranking of
security is done or optimisation is achieved (Fischer and Jordan 2008: 610-614).
6.2. Sampling Frame and Data
The study is based on 50 S&P CNX NIFTY companies that were part of the index since
November 3, 1995 to till date. S&P CNX NIFTY is recognised as a benchmark stock
index based on the selected stocks traded at the National Stock Exchange (NSE). It is
primarily owned and overseen by India Index Services and Products Ltd. (IISL), which
is joint venture (JV) between the NSE (1992), India’s most advanced and leading Stock
Exchange (3rd ranked world-wide) and Credit Rating and Information Services of India
Limited (CRISIL, 1987), India’s leading Credit Rating Company (1988-89) promoted by
the S&P. IISL is the first specialised company in the country focused upon developing
the stock indices as a core product by encompassing more than 20 sectors (24) in the
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
designed index, that is, NIFTY. In fact, this index was developed by Shah and Thomas
during nineties. It has a consulting and licensing agreement with the Standard & Poor’s
(S&P), who are world leaders in these services. It is noteworthy to mention that the
average traded value of all NIFTY stocks is more than 80% of the traded value of all
stocks available for trading on the NSE. The stocks are subject to inclusion in NIFTY
based on their (listed companies) average market capitalization, that is, more than or
equal to 500 crores; liquidity which is calculated on impact cost (ratio of actual buy/sell
size to ideal buy/sell size) which should be 0.75% or even less than that either for
buying or for selling the stocks and trade-frequencies of those stocks should be more
than 90% of total trades over six months period; lastly, floating stocks should be at least
of 12% which should not be held by promoters and associates or it is possible that 88%
of the total stocks can be held by them (for more details, see, Patwari and Bhargava
2009).
However, for the purpose of study the data are used from April, 2009 to March, 2010
(244-days closed-trade-price and since then, same 50 companies are the parts of this
index. NIFTY capital market segment’s market capitalization is around 37% (36.674),
while SENSEX excluding BSE-100, BSE-500, BSE-IPO, MIDCAP, SMLCAP and other
sectoral indices is reporting 63.326% as reported on December, 2009. In case of free-float
market capitalistion index, NIFTY (54.17%) is ahead of SENSEX (45.82%) other than or
excluding BSE-100. S&P CNX NIFTY is taken as market proxy and the average yields of
Government of India (GOI) securities are used as risk-free rate of returns of the
respective years. The data are collected from Centre of Monitoring Indian Economy (CMIE-
Prowess database), BSE, NSE, RBI, SEBI websites.
SECTION-IV
7. RESULTS AND DISCUSSIONS
Index data with respect to index return and stock return are retrieved from CMIE for
244-trading days-counts. Regressing index or market return on individual stock return
(taking natural-log of both return-series), beta is calculated for each 50-stock. Calculated
betas have achieved the precision of about 95% with the beta of the NSE-provided
database. 50 independent regressions are run to estimate the predictor or regressor, that
is, beta and unsystematic risk or residual variance (error component). Besides,
descriptive statistics are also ascertained for both the index- and stock-return series of
all 50-stocks cumulatively. The positive skewness coefficients indicate that frequency
distribution of index- and stock-returns series are positively skewed or have longer
thinner tail to the right. The unconditional distribution of both index and stock returns
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
0
10
20
30
40
50
60
70
80
-0.05 0.00 0.05 0.10 0.15
Series: INDEX_RETURN
Sample 1 243
Observations 243
Mean 0.002220
Median 0.001662
Maximum 0.163343
Minimum -0.060216
Std. Dev. 0.018848
Skewness 2.450687
Kurtosis 24.19185
Jarque-Bera 4790.317
Probability 0.000000
Descriptive Statistics_Index Retrun
exhibit thin tails (leptokurtic) and excessive peak at the mean than the corresponding
normal distributions. Both series follow an empirical distribution, say, log-normal,
normality is not achieved as reported by J-B (Jarque-Bera) statistic (4790.317 with
significant p-value for index return and 3838.90 with significant p-value for stock-return
series on daily-counts) besides the unit-root check, which is shown in the following
histogram and graph (Fig-1, Fig-2, and Fig-3). Here the J-B statistic is highly statistically
significant for both index and stock-returns series, and hence we fail to accept the null
hypothesis of normality.
Table-2 represents the results of Augmented Dickey-Fuller (ADF) (Dickey and Fuller
1979) unit-root tests applied on the log-first differences of daily stock- and index-
returns series to test the existence of unit roots and identify the order of integration
[I(1), in this case] of each variable. Phillips-Perron (PP) (Phillips and Perron, 1988) unit-
root test was not conducted to test the same as the sample-size is relatively large
enough to follow the asymptoticy. Results show that the first differences of logarithm of
the both index and stock-prices yielded larger ADF statistics that rejected the null
hypothesis with three critical values at three levels of significance, 1%, 5%, and 10%.
Hence, we can safely infer that both series are stationary at their first differences but
non-stationary processes are observed at their individual log-series. Therefore,
evidently, movements of stock-return series follow a mean-reverting process, which is
known as white noise (mean zero, variance, and covariance constant) conforming non-
linearity returns-series. Beta, F-statistic, Rj2, residual variance (σε2) of each stock are
presented in Exhibit-1.
FIG-1: Descriptive statistics of Index return (S&P CNX NIFTY)
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
-.10
-.05
.00
.05
.10
.15
.20
25 50 75 100 125 150 175 200 225
Stock Return
0
10
20
30
40
50
60
70
-0.05 0.00 0.05 0.10 0.15 0.20
Series: STOCK_RETURN
Sample 1 243
Observations 243
Mean 0.001987
Median 3.26e-05
Maximum 0.195857
Minimum -0.059181
Std. Dev. 0.023446
Skewness 2.519550
Kurtosis 21.80846
Jarque-Bera 3838.899
Probability 0.000000
FIG-2: Descriptive statistics of Stock return (50 stocks)
FIG-3: Pictorial presentation of NIFTY-stock return
Table 2: Results of Unit Root Tests
Variables ADF (t-statistic)
Levels
First Differences
dln Index_return (Rm) -10.15786*
dln Stock_return (Ri) -11.73572*
Note: The Mackinnon (1996) critical values for ADF test is -3.457, -2.873, -2.573 for both stock-returns series and index-returns series with one-sided p-values and lag-length is 5 (maximum 14) and lag-length 8 (maximum is 14) at 1%, 5%, and 10% significance levels, respectively. Information criterion chosen is SIC. * -indicates the significant-p-value rejecting the null-hypothesis.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
We have taken (regressed) predictor or beta to estimate the Sharpe-single index model
for the portfolio optimisation. Individual stock return (Ri), risk-free return (Rf) or T-bills
rate, that is, 4.7% annualised yield (0.035525% on daily count), beta (βj), market risk (σm2,
calculated from the daily-variance of the index-return), residual variance (σε2);-these
indicators are taken into consideration to calculate cut-off (C*) score to choose and select
the stock from the given index, NIFTY to formulate the portfolio. In fact, systematic risk
or βj-multiple of index-return-variance (β2σm2) to total risk (β2σm2 + σε2) is called “Sharpe-
appraisal ratio” (Bodie et al., 2002). Finally, Z-value for qualified individual stock is
calculated which is nothing but to assign certain weights to the selected stocks in the
portfolio or to arrive at the proportion of the stocks in the formulated portfolio or
“Sharpe-style analysis”, say, “N” stocks comprise of single-index portfolio following the
covariance terms, [(N2- N)/2]. In this case, 26 stocks are finally scored above C* or 0.253
to form a portfolio. Hence, total covariance-terms are 325 or NC26 out of 1225 (for the
index). Following the Markowitz’ approaches, number of covariance-terms are 377 out
of 1325. Enumeration satisfies the equation, that is, [N× (N+3)/2].
We have considered the market model approach other than constant return approach
(μi) to calculate the beta which is not exactly similar with CAPM. In market model, we
have incorporated market return (Rm) and individual stock return (Ri) where as i and βj
are chosen as coefficients of the OLS-regression model. CAPM takes into account of Rf
as replacement of and Rm as (Rm-Rf) the difference as excess market return or equity-
risk premium. Error component is considered as unsystematic risk that corroborates
residual variance or noise in the return-series of individual stock. This represents the
unexplained variance or residual sum square (RSS) in the stock’s or security’s return.
The following table provides an outlook of portfolio that is constructed after selecting
26-individual security from the given index, with respect to portfolio beta, R2, F-
statistic, and t-statistics with p-values at 5% level of significance, respectively. We try to
estimate the predictive ability of NIFTY as explanatory or exogenous variable on the
chosen portfolio as dependent or endogenous variable. β of the portfolio is 0.951
(standardized) and intercept is not significantly different from zero, that is, 0.168.
Explained variance of the model is almost 90% with moderate to good Durbin-Watson
statistic (2.009). Hence, we can say that the first differences of logarithm of the both
index and portfolio are free from serial correlation or auto-correlation problem and fail
to reject the robustness of the model as the model is devoid of “spurious regression
trap”. Residuals statistics are also mentioned in the table.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Table 3: Results of Regression
Dependent
Variable
Portfolio
Independent
Variable
Index (NIFTY)
R2 0.904 (0.573**) D-W 2.009
F-stat
(Goodness of fit
index)
2261.296**
Coefficients
Intercept (α) t-statistic 4.542 (0.037**)
Beta (β) t-statistic 47.553 (0.020**)
Residuals
statistics (N
=243)
Minimum Maximum Mean Std. deviation
Predicted value -5.43 15.35 0.37 1.752
Residual -2.118 2.633 0.000 0.572
Std. Predicted
value
-0.312 8.546 0.000 1.000
Std. Residual -3.696 4.593 0.000 0.998
Note: **-indicates significant p-values of the mentioned tests’ statistics at 5% level of significance,
respectively. In parentheses standard errors of the respective tests-statistics are mentioned.
Fig-4, 5, and 6 imply the pictorial presentation of portfolio’s actual, predicted and
residuals movement, frequency distributions or histogram (descriptive statistic), and
stationarity of regression standardised residuals, respectively.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
FIG-4: Actual-Predicted-Residual movement of the Portfolios
-8
-4
0
4
8
12
16
25 50 75 100 125 150 175 200 225
ACTUAL PREDICTED RESIDUAL
FIG- 5 &6: Histogram of the Portfolio and Normal P-P plot of Regression Resiudals
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Based on the C* and ratio analysis (Sharpe, Treynor, Jensen, and Sortino) we have
calculated the security’s rank in the chosen portfolio and down-side risk considering
calculation parameter, that is, minimum acceptable return (MAR) 0.05%. The following
tables 4 & 5 in view of post-modern portfolio theory provide the details of portfolio’s
average rank, security’s beta, annualised return, annualised standard deviation, etc.
Mean-variance efficient frontier using Markowitz’ two parameters approach is shown
in the following Fig-7.
FIG-7: Mean-Variance-Efficient Return of the Portfolio
Table-4: Post-Modern Portfolio Theory S&P CNX NIFTY Portfolio
Risk-Return Analysis
Sharpe Ratio 1.88 4.64
Downside Deviation (MAR) % 1.060 1.017
Downside Deviation (RFR) % 4.827 4.694
Downside Deviation (0%) 1.035 0.993
Sortino Ratio (MAR) 0.135 0.301
Sortino Ratio (RFR) -0.942 -0.934
Sortino Ratio (0%) 0.186 0.359
Mean Day Return (%) 0.22 0.37
Standard Deviation (%) 1.88 1.84
Compounding Daily Return (%) 0.19 0.36
Annualized Return (%) 60.04 138.24
Annualised SD (%) 29.44 28.79
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Sr No. Portfolio
Rank Order
Z -Value
Proportion/Weightage(%)
Annualised Ri
Annualised SD Beta
Sharpe Ratio Rank
Treynor Index
Rank
Jensen Index
Rank
Average Rank
1 A B B Ltd. 14 1.426 2.716 81.791 39.298 0.82 1.961 18 93.965 17 3.171 19 12.654
2
Ambuja Cements Ltd. 25 0.348 0.663 54.790 38.873 0.72 1.288 24 69.514 25 1.024 25 17.096
3 Axis Bank Ltd. 11 2.419 4.609 149.533 48.139 1.23 3.008 7 117.718 10 7.679 8 7.003
4
Bharat Petroleum Corpn. Ltd. 23 0.464 0.883 32.112 37.571 0.42 0.729 26 65.172 26 0.415 26 17.576
5 Cipla Ltd. 20 0.947 1.805 45.382 34.051 0.51 1.194 25 79.691 21 1.244 24 15.398
6 G A I L (India) Ltd. 21 0.606 1.155 55.041 35.452 0.68 1.419 23 73.972 24 1.270 23 16.140
7
H C L Technologies Ltd. 5 3.277 6.244 209.214 52.571 1.04 3.889 3 196.610 1
14.697 2 2.296
8 H D F C Bank Ltd. 3 3.714 7.076 85.028 30.712 0.76 2.614 10 105.642 12 3.827 15 9.871
9
Hero Honda Motors Ltd. 9 2.683 5.112 76.293 33.869 0.61 2.113 17 117.300 11 3.783 16 9.704
10
Hindalco Industries Ltd. 12 2.378 4.531 194.353 56.453 1.33 3.359 6 142.566 7
11.608 3 4.453
11 I C I C I Bank Ltd. 18 1.240 2.363 139.935 51.022 1.4 2.650 9 96.568 16 5.779 11 9.883
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Sr No. Portfolio
Rank Order
Z -Value
Proportion/Weightage(%)
Annualised Ri
Annualised SD Beta
Sharpe Ratio Rank
Treynor Index
Rank
Jensen Index
Rank
Average Rank
13
Infrastructure Development Finance Co. Ltd. 15 1.363 2.598 141.309 55.135 1.35 2.477 14 101.162 15 6.193 10 9.159
14
Kotak Mahindra Bank Ltd. 24 0.360 0.687 117.347 53.243 1.37 2.115 16 82.195 20 3.686 17 13.038
15 Larsen & Toubro Ltd. 16 1.255 2.392 119.481 44.643 1.26 2.570 12 91.064 18 4.508 13 11.190
16
Maruti Suzuki India Ltd. 17 1.244 2.370 66.667 37.007 0.7 1.673 21 88.467 19 2.322 21 13.891
17
Punjab National Bank 2 5.088 9.695 133.840 36.591 0.83 3.528 4 155.542 5 8.321 7 5.176
18
Ranbaxy Laboratories Ltd. 7 2.788 5.312 138.664 47.057 0.79 2.846 8 169.524 4 9.024 5 3.949
19 Siemens Ltd. 4 3.499 6.668 158.183 45.384 1.18 3.381 5 130.036 8 8.820 6 5.794
20
Steel Authority Of India Ltd. 13 1.577 3.005 130.244 48.391 1.24 2.594 11 101.213 14 5.694 12 9.531
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Sr No. Portfolio
Rank Order
Z -Value
Proportion/Weightage(%)
Annualised Ri
Annualised SD Beta
Sharpe Ratio Rank
Treynor Index
Rank
Jensen Index
Rank
Average Rank
22
Sun Pharmaceutical Inds. Ltd. 10 2.602 4.958 58.605 33.690 0.36 1.599 22 149.624 6 3.396 18 8.533
23 Tata Motors Ltd. 8 2.778 5.293 250.168 60.566 1.26 4.052 1 194.784 2
17.576 1 2.351
24 Tata Power Co. Ltd. 22 0.543 1.035 62.875 34.594 0.78 1.680 20 74.532 23 1.501 22 15.560
25 Tata Steel Ltd. 19 1.181 2.250 153.758 58.757 1.42 2.536 13 104.942 13 7.051 9 8.179
26 Wipro Ltd. 1 5.278 10.057 160.261 39.008 0.8 3.987 2 194.401 3 11.12
9 4 3.662
Portfolio 138.240 28.790 0.93 4.637 143.548 8.208
S&P CNX NIFTY 60.030 29.440 1 1.878 55.290
From the above Fig-7, it can be inferred that feasible region would be any point on the mean-variance efficient frontier
where tangency of potential portfolio would be a particular point intersecting the concave shaped curve. Sharpe-Linter
version postulates that with a decrease in tangency of potential portfolio or assets, grouping of assets are likely to be
increased. From the index, we have drawn 26 stocks that can form NC26 portfolios subject to the efficient frontier of the
minimum variance. Portfolio performs relatively better than index with respect to its annualised return (138.240% vs.
60.030%), annualised standard deviation (28.790% vs. 29.440%), the Sharpe-index (4.637 vs. 1.878), the Treynor-index
(143.548 vs. 55.290), and the Sortino-index (0.301 vs. 0.135), respectively. Jensen index of the portfolio is 8.208. Hence, all
four formulated hypotheses cannot be rejected or we fail to accept the null hypotheses. Coherent measures of risk (positive
homogeneity, sub-additivity, translation invariance, monotonicity) are considered while accomplishing the selection, evaluation
of the portfolio (for more details, see, Acerbi and Scandolo 2007; Hull 2007).
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
SECTION-V
8. SUMMARY AND CONCLUSION
The present study has touched upon the area of portfolio selection and evaluation in the
lights of both modern- and post-modern portfolio theories. Ratio-analysis is succinctly
interpreted and presented in order to improve the portfolio selection. Minimum-
variance portfolio is desired outcome if and only certain assumptions, namely, market
as proper vector space, no randomness or stochastic nature of the measured variables,
expected mean-shortfall or tail conditional expectancy (TCE) or conditional value-at-
risk (VaR), etc. are not violated while formulating hypotheses and methodology.
Sharpe’s single-index approach has taken care of portfolio selection and optimisation
well in this context. Although Sharpe’s postulations have possessed distinctiveness and
parsimony, that is, containment of minimum assumptions and minimum complexity,
incorporation of other ratios or indices have helped to improve or modify the portfolio
selection. Markowitz’s mean-variance efficient frontier is considered during the
determination of the portfolio’s risk- and return-equations.
We have chosen the NIFTY index as it serves a better proxy of the market than any
other indices, viz., BSE-SENSEX, BSE-midcap, BSE-100 etc., in Indian context. 50-stocks
are considered and Sharpe-algorithm is incorporated for calculating the cut-off score,
which comes about 0.253% on average-daily count basis. We have calculated beta,
residual variance by regressing index return on individual stock return considering
average yield of both index and stock on daily basis. Excess mean return and
cumulative beta to residual variance are calculated using the Sharpe single-index model
and then, other ratios are also determined to look at the top-26 stocks in regards to their
annualised returns, annualised standard deviations, betas, Sharpe-index scores,
Treynor-index scores, Jensen-index scores, and finally, we have arrived at average rank
of individual stock, the portfolio, and the index. Evidently, portfolio’s performance is
relatively superior to the index with respect to the Sharpe-ratio or index, Treynor-ratio,
Sortino-ratio, annualised return. Coefficient of determination (CD) shows that the
portfolio is a good mirror of the index and the standard deviation of the portfolio or the
systematic risk component is on lower side compared to the index. Hence, we conclude
that mean-variance efficient portfolio can be achieved by incorporating the Sharpe
single-index measure as an ex-ante approach, which would take care of portfolio risk-
return optimisation (with the given constraints). Therefore, a good combination of all
ratios incorporated in the paper provides a better ground to achieve the conformity of
both the modern- and post-modern portfolio theory.
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
EXHIBIT-1
Table-6: Results of regression (on average daily counts basis using high-frequency data)
Dependent
variable
Individual security (50 stocks)
Independent
variable
Index or NIFTY
Security’s name Model-R2 (%) Beta (t-Stat) F-Stat (GFI) Residual
variance (%)
ABB 38.078 0.823 (12.173**) 148.20** 0.000391
ACC 34.472 0.767 (12.259**) 126.78** 0.000397
Ambuja 29.814 0.720 (10.118**) 102.374** 0.000435
Axis Bank 56.775 1.232 (17.791**) 316.554** 0.000411
Bharat Heavy
Electricals
59.966 0.963 (18.999**) 360.991** 0.00022
Bharat
Petroleum
10.835 0.420 (5.411**) 29.286** 0.000516
Bharti 7.000 0.720 (4.260**) 18.151** 0.002451
Cairn Energy 47.415 0.946 (14.741**) 217.306** 0.000353
Cipla 19.639 0.512 (7.674**) 58.898** 0.000382
DLF 56.003 1.639 (17.514**) 306.764** 0.00075
GAIL 31.997 0.681 (10.648**) 113.399** 0.00035
HCL 33.390 1.039 (11.119**) 123.651** 0.000749
HDFC 53.310 0.761 (16.588**) 275.176** 0.00018
Hero Honda 28.706 0.616 (9.850**) 97.038** 0.000335
Hindalco 48.145 1.330 (14.958**) 223.760** 0.000677
Hindustan
Unilever
13.739 0.369 (6.195**) 38.387** 0.000305
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Security’s name Model-R2 (%) Beta (t-Stat) F-Stat (GFI) Residual
variance (%)
HDFC Ltd. 58.357 1.102 (18.377**) 337.737** 0.000308
ICICI Bank 64.951 1.396 (21.133**) 446.621** 0.000374
ITC 24.560 0.561 (8.857**) 78.459** 0.000345
Idea 45.122 1.097 (14.076**) 198.161** 0.000521
Infosys 33.494 0.645 (11.017**) 121.375** 0.000293
IDFC 52.260 1.353 (16.242**) 263.825** 0.000595
JAIPRAKASH 45.688 1.623 (14.239**) 202.74** 0.001113
JINDAL Steel 3.533 1.172 (2.970**) 8.826** 0.013343
Kotak Mahindra 57.159 1.367 (17.931**) 321.549** 0.000498
L&T 69.053 1.260 (23.189**) 537.772** 0.000253
M&M 13.684 1.038 (6.181**) 38.207** 0.002418
Maruti Suzuki 30.971 0.699 (10.398**) 108.130** 0.000387
NTPC 45.948 0.659 (14.313**) 204.870** 0.000182
ONGC 42.853 0.803 (13.443**) 180.723** 0.000306
Power Grid 55.804 0.859 (17.444**) 304.300** 0.000208
PNB 44.717 0.831 (13.962**) 194.941** 0.000303
RANBAXY 24.723 0.794 (8.896**) 79.153** 0.000683
Reliance Capital 61.682 1.577 (19.696**) 387.951** 0.000549
Reliance Comm 52.388 1.344 (16.284**) 265.18** 0.000548
RIL 20.634 1.271 (7.915**) 62.658** 0.00221
Reliance Infra 59.460 1.405 (18.801**) 353.487** 0.000478
Reliance Power 52.365 1.057 (16.276**) 264.931** 0.000361
Siemens 59.058 1.184 (18.645**) 347.640** 0.000346
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
Security’s name Model-R2 (%) Beta (t-Stat) F-Stat (GFI) Residual
variance (%)
SBI 62.835 1.153 (20.185**) 407.471** 0.00028
SAIL 57.198 1.243 (17.946**) 322.062** 0.000411
Sterlite 49.915 1.311 (15.497**) 240.184** 0.000613
Sun Pharma 9.897 0.359 (5.145**) 26.473** 0.000419
Suzlon 41.804 1.544 (13.157**) 173.12** 0.001179
TCS 7.432 0.735 (4.398**) 19.349** 0.002393
Tata Motors 37.803 1.264 (12.102**) 146.480** 0.000935
Tata Power 43.813 0.777 (13.708**) 187.926** 0.000276
Tata Steel 50.733 1.421 (15.753**) 248.178** 0.000697
Unitech 48.929 1.684 (15.195**) 230.893** 0.001053
Wipro 36.219 0.797 (11.698**) 136.86** 0.000398
Note: t-statistics are given in the parentheses; p-values of t-stat and F-stat are significant at 95%
level of confidence or at 5% level of significance (**). GFI implies for Goodness of Fit Index
Kushankur Dey & Debasish Maitra, Fellow Participant, IRMA
Draft Paper/IFID Conference/May-2010
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