EKOIST Journal of Econometrics and Statistics

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DOI :10.26650/ekoist.2022.37.1135040   IUP :10.26650/ekoist.2022.37.1135040    Full Text (PDF)

Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul

Müge Özdemir

The literature on finance defines the concept of an efficient market as a market where information about securities is instantly reflected in prices. Investors who trade on efficient markets cannot obtain abnormal returns. All market participants are assumed to have instant access to the information coming to the market, with everyone knowing the same information. The aim of this study is to test within the framework of information efficiency the weak-form efficiency market hypothesis using statistical tests with daily, weekly, and monthly frequencies for the BIST100 index over the period of October 2011-October 2021. The study uses the runs test, variance ratio test, unit root tests, structural break unit root tests, and nonlinear unit root tests to test weak form efficiency for this period. According to the findings, the BIST100 market index has been concluded to show a random walk at all frequencies in the relevant period (i.e., it has weak form efficiency).

Keywords: Weak-Form Efficiency Market, Random Walk, Nonlinear Unit Root Test, Structural Break Unit Root Test
JEL Classification : C12 , C58 , G14
DOI :10.26650/ekoist.2022.37.1135040   IUP :10.26650/ekoist.2022.37.1135040    Full Text (PDF)

Etkin Piyasa Hipotezinin Yapısal Kırılmalı ve Doğrusal Olmayan Birim Kök Testleri ile Analizi: Borsa İstanbul Üzerine Bir Uygulama

Müge Özdemir

Finans literatüründe menkul kıymetlerle ilgili bilgilerin anında fiyatlara yansıdığı piyasa kavramı etkin piyasa olarak tanımlanmaktadır. Etkin bir piyasada işlem yapan yatırımcılar anormal getiri elde edememektedir. Tüm piyasa katılımcılarının piyasaya gelen bilgilere anında ulaştığı ve herkesin aynı bilgiyi bildiği varsayılmaktadır. Bilgi etkinliği çerçevesinde, bu çalışmanın amacı, piyasa türlerinden biri olan zayıf formda etkin piyasa hipotezini BİST100 endeksi için 2011:10-2021:10 döneminde günlük, haftalık ve aylık frekanslarda istatistiki testler ile test etmektir. Çalışmada, söz konusu döneme ait verilerin zayıf formda etkinlik sınaması için runs testi, varyans oran testi, geleneksel birim kök testleri, yapısal kırılmalı birim kök testleri ve doğrusal olmayan birim kök testi kullanılmaktadır. Çıkan bulgulara göre, ilgili dönemde BİST100 piyasa endeksininin tüm frekanslarda rassal yürüyüş gösterdiği yani zayıf formda etkin olduğu sonucuna varılmaktadır.

Keywords: Zayıf Formda Etkin Piyasa, Rastgele Yürüyüş, Doğrusal Olmayan Birim Kök Testi, Yapısal Kırılmalı Birim Kök Test
JEL Classification : C12 , C58 , G14

EXTENDED ABSTRACT


Fama (1970)’s efficient market hypothesis argues all the information that occurs in this market to be instantly and correctly reflected in the prices of financial assets, with no investor able to obtain abnormal returns. According to this view, no asymmetric use of information occurs, and all research on efficient market theory is concerned with whether prices fully reflect certain subsets of information. Market efficiency is a theory that has been the subject of much debate and study in the finance literature.

This study analyzes market efficiency in accordance with the information taxonomy, which is categorized into three increasingly inclusive subsets, with the first considering the weak form of market efficiency, in which the information reflected in the prices consists of already observed historical prices. In this market type, an investor investing in the market is argued to be unable to expect abnormal returns in the future using historical data because the prices already reflect all that information, and it doesn’t provide a framework for any systematic abnormal returns. The second taxonomy considers the semi-strong form of market efficiency, in which prices reflect all past and current available information. As such, the information set is extended by including things such as current firm announcements and analysis reports into the precious information set. The third taxonomy conducts the strongform efficiency test to statistically prove or disprove whether investors with access to private or insider information are able to systematically achieve abnormal returns.

This study will test weak form efficiency by analyzing whether the BIST1000 stock market index complies with the random walk process. The data range covers the period of October 2011-October 2021, with the data being composed of the closing index values at daily, weekly, and monthly frequencies.

This study conducts the runs test, variance ratio test, traditional linear unit root test, structural break unit root test, nonlinear unit root test in order to test whether the series complies with the random walk hypothesis. The linear unit root and stationarity tests include the augmented Dickey-Fuller (1981), Phillips-Perron (1988), and Kwiatkowski–Phillips–Schmidt–Shin (KPSS, 1992) tests, while the unit root tests with structural breaks include the the Perron (1989), Zivot-Andrews (1992), LeeStrazicich (2003), and Kapetanios et al. (2003) nonlinear unit root tests. The runs test deals with whether the residuals are positive or negative, with the assumption that the residuals are independently distributed. The variance ratio test is used to test whether a random walk occurs in a series that is robust in terms of both constant variance and non-constant variance. The study uses the programs RATS (Regression Analysis of Time Series), EViews, and Stata for the tests.

According to the results, the price series at each frequency contain unit roots, and the variance ratio and runs tests support the unpredictability of the returns. As a result, analysis of the Bist100 index at daily, weekly, and monthly frequencies reveal the market to have a structure that supports the weak form of the efficient market hypothesis. Although this study found no difference in the results regarding different frequencies, no surprise would be had if divergent results were observed even for the same time series, as has been discussed in the literature. The ups and downs within each month were not observable due to the closing daily observation at the end of month being recorded as a monthly BIST100 data point. For example, the Perron test allows for a unit root with a structural break and revealed the BIST100 to exhibit its lowest reading as well as a structural break on March 23, 2020, which also coincides with the official start of the COVID-19 pandemic in Turkey.

For this reason, having individuals deal with the frequencies of the price series according to the maturity structure they have planned while investing would be a good decision. In this way, investors will be able to measure return and risk more accurately in the portfolios they have created. Investors who are unable to find a profitable opportunity in an efficient market can choose their investment preferences using an analysis that will detect the deviations in the price series with regard to their shortterm investment strategies. Checking the dynamics of international stock markets as well as BIST100 stocks would be additionally useful. Moreover, this study believes that future research should focus on nonlinear situations in the stock markets of other developing countries in order to better understand the extent to which information plays a role in portfolio strategies. The fact that investors in stock markets that do not comply with the random walk process and therefore do not provide the efficient market hypothesis are able to benefit from profitable opportunities in these markets through the arbitrage process is also worth mentioning. In summary, the results show that investors are not likely to systematically make profits using historical information on the BIST100; therefore, investors should base their investment strategies on this assumption. 


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References

  • Abraham, A., Seyyed, F. J., & Alsakran, S. A. (2002). Testing the random walk behavior and efficiency of the Gulf stock markets. Financial Review, 37(3), 469-480. google scholar
  • Aga, M., & Kocaman, B. (2008). Efficient market hypothesis and emerging capital markets: empirical evidence from Istanbul stock exchange. Inuternational Research Journal of Finance and Economics, 13(1), 131-144. google scholar
  • Aliyev, F. (2019). Testing market efficiency with nonlinear methods: Evidence from Borsa Istanbul. International Journal ofFinancial Studies, 7(2), 27. google scholar
  • Al-Loughani, N., & Chappell, D. (1997). On the validity of the weak-form efficient markets hypothesis applied to the London stock exchange. Applied Financial Economics, 7(2), 173-176. google scholar
  • Appiah-Kusi, J., & Menyah, K. (2003). Return predictability in African stock markets. Review of financial economics, 12(3), 247-270. google scholar
  • Bachelier, L. (1900). Théorie de la spéculation. In Annales scientifiques de l’École normale supérieure (Vol. 17, pp. 21-86). google scholar
  • Buguk, C., & Brorsen, B. W. (2003). Testing weak-form market efficiency: Evidence from the Istanbul Stock Exchange. International review of financial analysis, 12(5), 579-590. google scholar
  • Caner, M., & Hansen, B. E. (2001). Threshold autoregression with a unit root. Econometrica, 69(6), 1555-1596. google scholar
  • Chan, K. C., Gup, B. E., & Pan, M. S. (1997). International stock market efficiency and integration: A study of eighteen nations. Journal of business finance & accounting, 24(6), 803-813. google scholar
  • Chang, K. P., & Ting, K. S. (2000). A variance ratio test of the random walk hypothesis for Taiwan’s stock market. Applied Financial Economics, 10(5), 525-532. google scholar
  • Choudhry, T. (1994). Stochastic trends and stock prices: an international inquiry. Applied Financial Economics, 4(6), 383-390. google scholar
  • Christiano, L. J. (1992). Searching for a Break in GNP. Journal of Business & Economic Statistics, 10(3), 237-250. google scholar
  • Cooray, A., & Wickremasinghe, G. (2007). The efficiency of emerging stock markets: Empirical evidence from the South Asian region. The Journal of Developing Areas, 171-183. google scholar
  • Dickey, D. A., & Fuller, W. A. (1979). Distribution of the estimators for autoregressive time series with a unit root. Journal of the American statistical association, 74(366a), 427-431. google scholar
  • Dickey, D. A., & Fuller, W. A. (1981). Likelihood ratio statistics for autoregressive time series with a unit root. Econometrica: journal of the Econometric Society, 1057-1072. google scholar
  • Fama, E. F., & French, K. R. (1988). Permanent and temporary components of stock prices. Journal of political Economy, 96(2), 246-273. google scholar
  • Fama, E.F., (1970), “Efficient Capital Markets: A Review of Theory and Empirical Word”, Journal of Finance, Vol.35, 383-417. google scholar
  • Fama, E.F., French, K.R., (1993), “Common Risk Factors in the Returns on Stocks and Bonds”, Journal of Financial Economics, Vol. 33, No. 1, 3-56. google scholar
  • Fawson, C., Glover, T. F., Fang, W., & Chang, T. (1996). The weak-form efficiency of the Taiwan share market. Applied Economics Letters, 3(10), 663-667. google scholar
  • Gan, C., Lee, M., Yong, H. H. A., & Zhang, J. (2005). Revisiting share market efficiency: evidence from the New Zealand, Australia, US and Japan stock indices. American Journal of Applied Sciences, 2(5), 996-1002. google scholar
  • Gilmore, C. G., & McManus, G. M. (2003). Random-walk and efficiency tests of Central European equity markets. Managerial Finance, 29(4), 42-61. google scholar
  • Gozbasi, O., Kucukkaplan, I., & Nazlioglu, S. (2014). Re-examining the Turkish stock market efficiency: Evidence from nonlinear unit root tests. Economic Modelling, 38, 381-384. google scholar
  • Groenewold, N. (1997). Share market efficiency: tests using daily data for Australia and New Zealand. Applied Financial Economics, 7(6), 645-657. google scholar
  • Grossman, S. J., & Stiglitz, J. E. (1980). On the impossibility of informationally efficient markets. The American economic review, 70(3), 393-408. google scholar
  • Hamid, K., Suleman, M. T., Ali Shah, S. Z., Akash, I., & Shahid, R. (2010). Testing the weak form of efficient market hypothesis: Empirical evidence from Asia-Pacific markets. International Research Journal of Finance and Economics, Issue 58, 121-133. google scholar
  • Hasanov, M. (2009). Is South Korea’s stock market efficient? Evidence from a nonlinear unit root test. Applied Economics Letters, 16(2), 163-167. google scholar
  • Hasanov, M., & Omay, T. (2007). Are the transition stock markets efficient? Evidence from nonlinear unit root tests. Central Bank Review, 7(2), 1-7. google scholar
  • Hassan, K. M., Al-Sultan, W. S., & Al-Saleem, J. A. (2003). Stock market efficiency in the gulf cooperation council countries (GCC): The case of Kuwait stock exchange. Development, 1(1), 1-21. google scholar
  • Hepsag, A., & Akcali B. Y. (2015). Zayıf formda piyasa etkinliğinin asimetrik doğrusal olmayan birim kök testi ile analizi: G-7 ve E-7 ülkeleri örneği. BDDK Bankacılık ve Finansal Piyasalar Dergisi, 9(2), 73-90. google scholar
  • Kapetanios, G., Shin, Y., & Snell, A. (2003). Testing for a unit root in the nonlinear STAR framework. Journal of econometrics, 112(2), 359-379. google scholar
  • Karemera, D., Ojah, K., & Cole, J. A. (1999). Random walks and market efficiency tests: Evidence from emerging equity markets. Review of Quantitative finance and Accounting, 13(2), 171-188. google scholar
  • Kendall, M. G., & Hill, A. B. (1953). The analysis of economic time-series-part i: Prices. Journal of the Royal Statistical Society. Series A (General), 116(1), 11-34. google scholar
  • Kilic, Y. (2020). Adaptive Market Hypothesis: Evidence from the Turkey Stock Market. Journal of Applied Economics & Business Research, 10(1). google scholar
  • Kilic, Y., & Fatih, M. B. (2016). The efficient market hypothesis: Evidence from Turkey. International Journal of Academic Research in Business and Social Sciences, 6(10), 262-272. google scholar
  • Kwiatkowski, D., Phillips, P. C., Schmidt, P., & Shin, Y. (1992). Testing the null hypothesis of stationarity against the alternative of a unit root: How sure are we that economic time series have a unit root?. Journal of econometrics, 54(1-3), 159-178. google scholar
  • Laurence, M. M. (1986). Weak-form efficiency in the Kuala Lumpur and Singapore stock markets. Journal of Banking & Finance, 10(3), 431-445. google scholar
  • Lee, J., & Strazicich, M. C. (2003). Minimum Lagrange multiplier unit root test with two structural breaks. Review of economics and statistics, 85(4), 1082-1089. google scholar
  • Lee, J., & Strazicich, M. C. (2004). Minimum LM Unit Root Test with One Structural Break (No. 04-17). google scholar
  • Lee, U. (1992). Do stock prices follow random walk?: Some international evidence. International Review of Economics & Finance, 1(4), 315-327. google scholar
  • LeRoy, S. F. (1973). Risk aversion and the martingale property of stock prices. International Economic Review, 436-446. google scholar
  • Lim, K. P., Brooks, R. D., & Kim, J. H. (2008). Financial crisis and stock market efficiency: Empirical evidence from Asian countries. International Review of Financial Analysis, 17(3), 571-591. google scholar
  • Lintner, J. (1965). Security prices, risk, and maximal gains from diversification. The journal of finance, 20(4), 587-615. google scholar
  • Lintner, J. (1975). The valuation of risk assets and the selection of risky investments in stock portfolios and capital budgets. In Stochastic optimization models in finance (pp. 131-155). Academic Press. google scholar
  • Lo, A. W., & MacKinlay, A. C. (1988). Stock market prices do not follow random walks: Evidence from a simple specification test. The review of financial studies, 1(1), 41-66. google scholar
  • Mandelbrot, B. (1966). Forecasts of future prices, unbiased markets, and” martingale” models. The Journal of Business, 39(1), 242-255. google scholar
  • Mobarek, A., & Fiorante, A. (2014). The prospects of BRIC countries: Testing weak-form market efficiency. Research in international Business and Finance, 30, 217-232. google scholar
  • Moustafa, M. A. (2004). Testing the weak-form efficiency of the United Arab Emirates stock market. International journal of business, 9(3). google scholar
  • Narayan, Kumar, P. (2005). Are the Australian and New Zealand stock prices nonlinear with a unit root?. Applied Economics, 37(18), 2161-2166. google scholar
  • Narayan, P. K., & Smyth, R. (2004). Is South Korea’s stock market efficient?. Applied Economics Letters, 11(11), 707-710. google scholar
  • Nisar, S., & Hanif, M. (2012). Testing weak form of efficient market hypothesis: empirical evidence from South Asia. World Applied Sciences Journal, 17(4), 414-427. google scholar
  • Oktay, T. A. S., & Atac, C. G. (2005). Testing random walk hypothesis for Istanbul stock exchange. PressAcademia Procedia, 9(1), 48-53. google scholar
  • Osborne, M. F. (1959). Brownian motion in the stock market. Operations research, 7(2), 145-173. google scholar
  • Osborne, M. F. (1962). Periodic structure in the Brownian motion of stock prices. Operations Research, 10(3), 345-379. google scholar
  • Ozdemir, Z. A. (2008). Efficient market hypothesis: evidence from a small open-economy. Applied Economics, 40(5), 633-641. google scholar
  • Özdemir, M. (2018). Kantil birim kök testleri: kırılgan beşli ülkelerinde enflasyonun kalıcılığının analizi. Yayımlanmamış Yükseklisans Tezi, İstanbul. google scholar
  • Perron, P. (1989). The great crash, the oil price shock, and the unit root hypothesis. Econometrica: journal of the Econometric Society, 1361-1401. google scholar
  • Phillips, P. C., & Perron, P. (1988). Testing for a unit root in time series regression. Biometrika, 75(2), 335-346. google scholar
  • Samuelson, P.A., (1965), “Proof That Properly Anticipated Prices Fluctuate Randomly, Industrial Management Review, Vol. 6, No. 2, 41-49. google scholar
  • Schmidt, P., & Phillips, P. C. (1992). LM tests for a unit root in the presence of deterministic trends. Oxford bulletin of economics and statistics, 54(3), 257-287. google scholar
  • Sewell, M. (2012). The efficient market hypothesis: Empirical evidence. International Journal of Statistics and Probability, 1(2), 164. google scholar
  • Sharpe, W. F. (1964). Capital asset prices: A theory of market equilibrium under conditions of risk. The journal of finance, 19(3), 425-442. google scholar
  • Smith, G., & Ryoo, H. J. (2003). Variance ratio tests of the random walk hypothesis for European emerging stock markets. The European Journal of Finance, 9(3), 290-300. google scholar
  • Urrutia, J. L. (1995). Tests of random walk and market efficiency for Latin American emerging equity markets. Journal of financial research, 18(3), 299-309. google scholar
  • Worthington, A. C., & Higgs, H. (2004). Random walks and market efficiency in European equity markets. Global Journal of Finance and Economics, 1(1), 59-78. google scholar
  • Zivot, E., & Andrews, D. W. (1992). Further Evidence on the Great Crash, the Oil-Price Shock, and the Unit-Root Hypothesis. Journal of Business & Economic Statistics, 10(3). google scholar

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APA

Özdemir, M. (2022). Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul. EKOIST Journal of Econometrics and Statistics, 0(37), 257-282. https://doi.org/10.26650/ekoist.2022.37.1135040


AMA

Özdemir M. Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul. EKOIST Journal of Econometrics and Statistics. 2022;0(37):257-282. https://doi.org/10.26650/ekoist.2022.37.1135040


ABNT

Özdemir, M. Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul. EKOIST Journal of Econometrics and Statistics, [Publisher Location], v. 0, n. 37, p. 257-282, 2022.


Chicago: Author-Date Style

Özdemir, Müge,. 2022. “Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul.” EKOIST Journal of Econometrics and Statistics 0, no. 37: 257-282. https://doi.org/10.26650/ekoist.2022.37.1135040


Chicago: Humanities Style

Özdemir, Müge,. “Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul.” EKOIST Journal of Econometrics and Statistics 0, no. 37 (Dec. 2023): 257-282. https://doi.org/10.26650/ekoist.2022.37.1135040


Harvard: Australian Style

Özdemir, M 2022, 'Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul', EKOIST Journal of Econometrics and Statistics, vol. 0, no. 37, pp. 257-282, viewed 4 Dec. 2023, https://doi.org/10.26650/ekoist.2022.37.1135040


Harvard: Author-Date Style

Özdemir, M. (2022) ‘Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul’, EKOIST Journal of Econometrics and Statistics, 0(37), pp. 257-282. https://doi.org/10.26650/ekoist.2022.37.1135040 (4 Dec. 2023).


MLA

Özdemir, Müge,. “Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul.” EKOIST Journal of Econometrics and Statistics, vol. 0, no. 37, 2022, pp. 257-282. [Database Container], https://doi.org/10.26650/ekoist.2022.37.1135040


Vancouver

Özdemir M. Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul. EKOIST Journal of Econometrics and Statistics [Internet]. 4 Dec. 2023 [cited 4 Dec. 2023];0(37):257-282. Available from: https://doi.org/10.26650/ekoist.2022.37.1135040 doi: 10.26650/ekoist.2022.37.1135040


ISNAD

Özdemir, Müge. “Analyzing the Efficient Market Hypothesis with the Structural Break and Nonlinear Unit Root Tests: An Application on Borsa Istanbul”. EKOIST Journal of Econometrics and Statistics 0/37 (Dec. 2023): 257-282. https://doi.org/10.26650/ekoist.2022.37.1135040



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Submitted23.06.2022
Accepted10.11.2022
Published Online29.12.2022

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