On the stock market, information about listed companies as profits, risks and other important
information is calculated and published daily in the market to help investors consider, weight out
investment decisions. One of the important parameter reflecting the risk of stocks is the beta
coefficient (β). Base on the database of three garment and textile companies posted up on Hanoi
Stock Exchange, the study computed beta coefficient of each company. The result shows that TNG
stocks are lots of prospects and have smallest volatility, safety group, less risky compared to other
stocks in the same industry such as TET, NPS.
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Nguyễn Văn Huy và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 117(03): 119 - 123
119
THE CALCULATION OF BETA COEFFICIENT
OF SOME COMPANIES POSTED UP HANOI STOCK EXCHANGE
Nguyen Van Huy
*
, Ngo Thi Huyen Trang
College of Economics and Business Administration – TNU
SUMMARY
On the stock market, information about listed companies as profits, risks and other important
information is calculated and published daily in the market to help investors consider, weight out
investment decisions. One of the important parameter reflecting the risk of stocks is the beta
coefficient (β). Base on the database of three garment and textile companies posted up on Hanoi
Stock Exchange, the study computed beta coefficient of each company. The result shows that TNG
stocks are lots of prospects and have smallest volatility, safety group, less risky compared to other
stocks in the same industry such as TET, NPS.
Key words: Beta coefficient, stock returns, risk, garment and textile
INTRODUCTION
*
Vietnam‟s stock market had come into
operations since July 28
th
, 2000 with the first
session at the center of Ho Chi Minh City
Stock Exchange. After more than 12 years of
operation, Vietnamese stock market has
achieved significant growth. Up till now,
Vietnamese stock market has 2 stock
exchanges which are HOSE (Ho Chi Minh
Stock Exchange) and HNX (Hanoi Stock
Exchange) have 105 active stock companies
with about 716 security ticker. On the stock
market, information about listed companies as
profits, risks and other important information
is calculated and published daily in the
market to help investors consider, weight out
investment decisions. One of the important
parameter reflecting the risk of stocks is the
beta coefficient (β). Beta coefficient is the
coefficient measuring the known volatility or
a measure of systematic risk of a security or a
portfolio which is relevant to the overall
market. The purpose of this paper is to
calculate the Beta coefficient of three garment
and textile companies which are TNG
Trading and Investment Joint Stock
Company, Northern Textiles and Garments
Joint Stock Company (TET) and Phu Thinh –
Nha Be Garment joint Stock Company (NPS)
posted up Hanoi Stock Exchange.
*
Tel: 0949 275666, Email: huytueba@gmail.com
BETA COEFFICIENT
Beta, also known as the beta coefficient,
which is the coefficient measuring the known
volatility is a measure of systematic risk of a
security or a portfolio relative to the overall
market. Beta coefficient is a key parameter in
the capital asset pricing model (CAPM). Beta
is calculated based on the regression analysis
and you can think of beta as the tendency and
the degree of reaction to the volatility of the
stock market. In finance, the Beta (β) of a
stock or portfolio is a number describing the
correlated volatility of an asset in relation to
the volatility of the benchmark that said asset
is being compared to.
The formula for Beta
The actual definition of beta is:
Where is the covariance
between the return on asset and the return
on the market portfolio and is the
variance of the market.
One useful property is that the average beta
across all securities, when weighted by the
proportion of each security‟s market value to
that of the market portfolio, is 1. That is:
Nguyễn Văn Huy và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 117(03): 119 - 123
120
Table 1. Characteristics of Beta
Value of beta Interpretation
Asset generally moves in the opposite direction as compared to the index
Movement of the asset is uncorrelated with the movement of the benchmark
Movement of the asset is generally in the same direction as, but less than the
movement of the benchmark
Movement of the asset is generally in the same direction as, and about the same
amount as the movement of the benchmark
Movement of the asset is generally in the same direction as, but more than the
movement of the benchmark
Where is the proportion of security s
market value to that of the entire market and
is the number of securities in the market.
Equation is intuitive, one you think about it. If
you weight all securities by their market
values, the resulting portfolio is the market.
By definition, the beta of the market portfolio
is 1. That is, for every 1 percent movement in
the market, the market must move 1 percent-
by definition. Beta is also referred to
as financial elasticity or correlated
relative volatility, and can be referred to as a
measure of the sensitivity of the asset‟s
returns to market returns, its non-diversifiable
risk, its systematic risk, or market risk. On an
individual asset level, measuring beta can
give clues to volatility and liquidity in the
marketplace. In fund management, measuring
beta is thought to separate a manager‟s skill
from his or her willingness to take risk.
The beta coefficient was born out of linear
regression analysis. It is linked to a regression
analysis of the returns of a portfolio (such as a
stock index) (x-axis) in a specific period
versus the returns of an individual asset (y-
axis) in a specific year. The regression line is
then called the Security characteristic
line (SCL).
Yt = α + βx + ε
α is called the asset‟s alpha and β is called the
asset‟s beta coefficient. Both coefficients
have an important role in Modern portfolio
theory.
Standard Deviation )
Stock Volume
Source: Zvi Bodie, Alex Kane, Alan J.
Marcus, “Investments”. 8th Ed., [279–318]
Significance of Beta coefficients
The stock‟s beta coefficient, said its profit
rate volatility compared to market returns.
Coefficient can be a positive or a negative.
The stock has a positive number coefficient,
its profits positively relationship with market
income. Conversely, stocks with negative
values will have a relationship in the opposite
direction to the market.
METHODOLOGY
We downloaded data about the trading price
of 3 listed companies during the period from
28/12/2006 to 30/12/2012 on HNX. Apply
single index model for the price of 3 figures
on HNX securities taken in the period to find
Entire risks
Nonsystematic risks
Systematic risks
Nguyễn Văn Huy và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 117(03): 119 - 123
121
their beta coefficients. First, the last price of
trading session we calculate the rate of
change of the price the next day than the day
before, that‟s the level of profitability of the
stock that day. Profitability of the day is
calculated by the following formula:
Ri = x 100
Then, using the least squares method to
estimate beta. Specifically, here we use the
Slope function in excel with Ri is the return
of stock i and RM is the return of the HNX-
Index on the day, or to use SPSS regression
between rate rates of return on stock i and the
profitability of the market. Based on the
calculation results of the 3 stocks on HNX,
we can know the attributes listed companies
in the group yet groups: the group of high-risk
stocks, stocks with medium risk, the group of
low-risk stocks. In our opinion, the group of
high risks stocks are stocks with a beta greater
than 1.2. That is, stocks with large price
fluctuations than 20% compared with the
general volatility of the HNX-Index. So, this
group is suitable for adventurous investors
want higher profits and not risk-averse.
Stocks with average risk stocks with beta
coefficients ranging from 0.8 to 1.2. That is,
this group‟s share price may fluctuate in the
range of less than 20% compared with the
general volatility of the market. So, this is the
group of stocks with the balance of risk and
return. Stocks are less risky stocks with a beta
less than 0.8. These stocks are considered
safe. That is, if the market goes down, the
stocks in this group decreased less. However,
in exchange for benefits from investing in
stocks is not high.
RESULTS
Table 2 reports the number of stocks traded,
the mean, the standard deviation, the
skewness, the excess kurtosis, the first order
serial correlation and the number of times a
stock is not normally distributed for three
stocks, the total market index and three sub
periods from November 2007 to October
2012 of TNG, from April 2010 to October
2012 of TET and from October 2006 to
October 2012 of NPS.
The standard deviation represents the
volatility of stocks. Table 4.1 shows that the
average volatility of the volatility of the three
stocks: TNG: 4,1%; TET: 3,5% and NPS:
4,7%. The volatility of stocks is the highest
NPS and the stocks TNG, TET smaller
volatility. The skewness and excess kurtosis
says something about the position and form of
the distribution of the ordinary stock returns.
If a distribution in positively skewed the
ordinary returns of a stock are characterized
by many small losses and some extreme gains
the reverse is true for negatively skewed
ordinary returns. In table 1 the biggest
difference in skewness in between the average
skewness of the 3 stocks, which is TET and
the total market skew of -0,35. This means
that the stock are characterized on average by
more small losses and few very high gains
and the total market index is characterized by
many small gains and few extreme losses.
With the Kurtosis NPS shares have Kurtosis:
49 greater than 3 should have a very high
kurtosis. The stock TNG and TET co kurtosis
respectively is 1.65 and 2.64 less than 3
should is flat
Table 2: Descriptive Statistics of TNG, TET and NPS
Descriptive Statistics TNG TET NPS
Mean -0.00048 -0.00081 0.00128
Standard Error 0.0012 0.0013 0.0012
Count 1305 703 1521
Skewness 0.37 -0.35 2.55
Standard Deviation 0.042 0.035 0.047
Nguyễn Văn Huy và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 117(03): 119 - 123
122
Sample Variance 0.0018 0.0012 0.0022
Kurtosis 1.65 2.64 49.01
Using the data collected of Stocks TNG (from
2008 to 2012), TET (from 2010 to 2012),
NPS (from 2007 to 2012) and the formula for
Beta:
The study used the SLOPE formula in Excel
use to determine the beta of three stocks, and
after the results are calculated as follows:
Beta of TNG: β = 0.179; Beta of TET: β =
0.003; Beta of NPS: β = 0.159. After beta
calculation, we can see that all three betas are
in the range of 0 <β < 1, it can tell us that the
movement of the asset is generally in the
same direction as, but less than the movement
of the market. So if there is a big change in
the market, the beta of TET will move a little
in compare with 2 other betas (TNG and
NPS). Furthermore, looking at the third beta
of the stocks we know that all 3 stocks with
the safety group under 0.8 Beta. There is very
little variation with changes in the market, ie
if the market is reduced to little effect on the
stock price of three stocks. TNG shares have
the largest beta, it tells us that the volatility of
the stock return of TNG is greater than two
remaining companies is TET and NPS. It says
stocks TNG may yield the highest return
among three stocks. Stocks TET is little
volatility, so the profitability is very low.
CONCLUSION AND IMPLICATIONS
TNG stocks are lots of prospects compared to
other stocks in the same industry as TET,
NPS as we have analyzed above. Stocks of
TNG has smallest volatility index in the three
stocks index level and has index of the
highest profits. In summary, the stocks TNG,
we believe that in the long term, it may be
profitable for investors if the current price
does not reflect the actual value. Stocks TNG
is consistent with all these new investors,
stocks of TNG in the safety group, less risk
and stability in stocks TNG bring for
investors. The transaction price is an index
reflecting all information about the
company‟s operations. But in Vietnam, the
price is only a small part of the business,
largely due to the impact from supply and
demand for shares of speculators. In
particular, investors sentiment as “herd”, or
“crowd effect" always strongly dominant
stocks prices. Therefore, beta is calculated
from the price can‟t speak of business risk.
The second is the market portfolio. In this
article, main indicators used are HNX-Index
with 3 shares represented the textile industry
is TNG, TET and NPS. This index is not
enough to create a market portfolio, because
this list is not fully companies in the field of
textile and garment industries. Therefore, the
volatility of the portfolio is not accurate
assessment of the volatility of textile industry
in the economy. The stocks listed on the stock
exchanges is too short, the longest is since the
end of 2006, so price data is not long enough
to be able to conduct regression beta
coefficient found accurate. With the above
restrictions, beta hardly meaningful if
calculated at this stage. However, the beta is
still very useful if we use it properly. Come
back to the essence of the first beta, which is
a statistical tool that measures the ability of
the stock volatility than the volatility of the
market. We can use the beta as an indicator in
technical analysis. Accordingly, when the
beta starts exceeded 1, if HNX index
increased, the signs will be the time to buy
because the stock price will increase by the
increase in the market index. Conversely, if
the index should be decreased because the
value of securities sold will reduction by the
decrease of the index.
REFERENCES
1. Markowitz, H.M. (March 1952). “Portfolio
Selection”. The Journal of Finance 7 (1): [77].
2. Horcher, Karen A. (2005). “Essentials of
financial risk management”. John Wiley and
Sons. [1–3].
3. Ross, Stephen. (1976). “The Arbitrage Theory
of Capital Asset Pricing”. “Journal of Economic
Theory 13 (December)”: [341-60].
Nguyễn Văn Huy và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 117(03): 119 - 123
123
4. “Stock Basics”, Investor Guide.com.
5. Zvi Bodie, Alex Kane, Alan J. Marcus,
“Investments”. 8th Ed., [279–318]
8. Klarman, Seth; Williams, Joseph (1991).
"Beta". “Journal of Financial Economics 5 (3)”: [117]
9. French, Craig W. (2003). "The Treynor Capital
Asset Pricing Model". “Journal of Investment
Management 1 (2)”: [60–72]
10. Arnold, Glen (2005). “Corporate financial
management” (3. ed. ed.). “Harlow: Financial
Times/Prentice Hall.” [354].
11. Breeden, Douglas (September, 1979). "An
intertemporal asset pricing model with stochastic
consumption and investment opportunities". “Journal
of Financial Economics 7” (3): [265–296].
12. Fama, Eugene F. and Kenneth French
(1992). “The Cross-Section of Expected Stock
Returns”. “Journal of Finance” [427-466].
13. Ross, Westerfield, Jaffe, Jordan. “Corporate
Finance Core Principles & Applications”. 2st
Ed.., [324 – 365].
14. Nguyen Ngoc Vu (2010), “The calculation of
ß coefficient of some companies posted up at
HNX”, Journal of science and technology,
University of Danang. No. 2 (37)
TÓM TẮT
TÍNH TOÁN HỆ SỐ BETA CỦA MỘT SỐ CÔNG TY
NIÊM YẾT TRÊN SÀN CHỨNG KHOÁN HÀ NỘI (HNX)
Nguyễn Văn Huy*, Ngô Thị Huyền Trang
Trường Đại học Kinh tế & Quản trị Kinh doanh – ĐH Thái Nguyên
Trên thị trƣờng chứng khoán, thông tin của các công ty niêm yết nhƣ lợi nhuận, rủi ro và các thông
tin khác đƣợc tính toán và công bố hàng ngày trên thị trƣờng giúp các nhà đầu tƣ xem xét và đƣa
ra quyết định đầu tƣ. Một trong những tham số phản ánh rủi ro của cổ phiếu là hệ số beta. Dựa trên
dữ liệu của 3 công ty may mặc niêm yết trên sàn chứng khoán Hà Nội, nghiên cứu tính toán hệ số
beta cho từng công ty. Nghiên cứu chỉ ra rằng cổ phiếu TNG có nhiều triển vọng, ít biến động, vào
nhóm an toàn, ít rủi ro khi so sánh với các cổ phiếu trong cùng ngành nhƣ TET và NPS.
Từ khóa: Hệ số beta, lợi nhuận cổ phiếu, rủi ro, các công ty may mặc
Ngày nhận bài:16/12/2013; Ngày phản biện:31/12/2013; Ngày duyệt đăng: 17/3/2014
Phản biện khoa học: TS. Đỗ Đình Long – Trường Đại học Kinh tế & Quản trị Kinh doanh - ĐHTN
*
Tel: 0949 275666, Email: huytueba@gmail.com
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