New evidence from the random walk hypothesis for BRICS stock indices: a wavelet unit root test approach

2014 ◽  
Vol 43 ◽  
pp. 38-41 ◽  
Author(s):  
Aviral Kumar Tiwari ◽  
Phouphet Kyophilavong
2021 ◽  
Vol 14 (1) ◽  
pp. 18
Author(s):  
Dwi Tjahjo Purnomo

<p><em><span lang="EN-US">Berbeda dengan saham lain yang turun cukup tajam saat dimulainya pandemi Covid-19, pergerakan harga saham farmasi justru mengalami peningkatan. Kenaikan harga saham farmasi sejalan dengan ekspektasi investor terhadap peningkatan permintaan obat dan suplemen kesehatan yang berdampak pada kenaikan harga saham di pasar. Penelitian ini secara empiris bertujuan untuk menguji perilaku rantai jual beli di Bursa Efek Indonesia (BEI) yaitu PT Indo Farma Tbk (INAF), PT Kimia Farma Tbk (KAEF), PT Kalbe Farma Tbk (KLBF), PT Phapros Tbk (PEHA), PT Pyridam Farma Tbk (PYFA), dan PT Tempo Scan Pacific Tbk (TSPC). Secara khusus, penelitian ini menyelidiki apakah akan melaporkan apakah saham farmasi selama Pandemi Covid-19 mengikuti Random Walk Hypothesis (RWH) atau sebaliknya apakah pergerakan harga dapat diprediksi. Data yang digunakan dalam penelitian ini adalah harga penutupan saham harian dari tanggal 2 Januari 2020 sampai dengan 2 Februari 2021. Data dianalisis menggunakan uji Augmented Dickey-Fuller untuk adanya Uji Unit Root, uji Variance Ratio, dan Autoregressive Moving Average. (ARMA). Hasilnya, berdasarkan Uji Akar Unit, semua data stasioner di tingkat. Pengujian lebih lanjut menggunakan Variance Ratio, baik secara stand alone intersep maupun trend dan antar semua data juga tidak bergerak secara acak dan tidak mengikuti Hipotesis Random Walk. Terakhir, dengan menggunakan model ARMA, pergerakan log return saham farmasi di BEI dapat diprediksi.</span></em></p><p><em><span lang="EN-US"><em><span>In contrast to other stocks that fell quite sharply at the start of the Covid-19 pandemic, pharmaceutical stock price movements have increased. The increase in the price of pharmaceutical stocks is in line with investors' expectations of an increase in demand for medicines and health supplements, which will have an impact on the increase in stock prices in the market. This study empirically aims to examine the behavior of the chain buying and selling on the Indonesia Stock Exchange (IDX), namely PT Indo Farma Tbk (INAF), PT Kimia Farma Tbk (KAEF), PT Kalbe Farma Tbk (KLBF), PT Phapros Tbk (PEHA), PT Pyridam Farma Tbk (PYFA), and PT Tempo Scan Pacific Tbk (TSPC). Specifically, this study investigates whether to report whether pharmaceutical stocks during the Covid-19 Pandemic followed the Random Walk Hypothesis (RWH) or vice versa whether the price movements were predictable. The data used in this study are daily stock closing prices from January 2, 2020, to February 2, 2021. The data were analyzed using the Augmented Dickey-Fuller test for the existence of the Unit Root Test, Variance Ratio test, and Autoregressive Moving Average (ARMA). The result, based on the Unit Root Test, all data is stationary at the level. Further testing using the Variance Ratio, both by stand-alone intercept and trend and between all data also does not move randomly and does not follow the Random Walk Hypothesis. Finally, using the ARMA model, the log return movement of pharmaceutical stocks in IDX can be predicted.</span></em></span></em></p>


2007 ◽  
Vol 10 (01) ◽  
pp. 15-31 ◽  
Author(s):  
Hooi Hooi Lean ◽  
Russell Smyth

This paper applies univariate and panel Lagrange Multiplier (LM) unit root tests with one and two structural breaks to examine the random walk hypothesis for stock prices in eight Asian countries. The results from the univariate LM unit root tests and panel LM unit root test with one structural break suggest that stock prices in each country is characterized by a random walk, but the findings from the panel LM unit root test with two structural breaks suggest that stock prices in the eight countries are mean reverting.


2017 ◽  
Vol 50 (4) ◽  
pp. 441-454 ◽  
Author(s):  
Mohsen Bahmani-Oskooee ◽  
Tsangyao Chang ◽  
Zahra (Mila) Elmi ◽  
Omid Ranjbar

2020 ◽  
Vol 65 ◽  
pp. 187-198
Author(s):  
Yi-Lung Lee ◽  
Omid Ranjbar ◽  
Fateme Jahangard ◽  
Tsangyao Chang

2021 ◽  
Vol 13 (2) ◽  
pp. 79-88
Author(s):  
Janesh Sami

The main goal of this paper is to investigate the random walk hypothesis in Fiji using monthly data from January 2000 to October 2017. Applying augmented Dickey Fuller (ADF 1979, 1981) and Phillips-Perron (1988), Zivot-Andrews (1992), and Narayan and Popp (2010) unit root tests, this study finds that stock prices is best characterized as non-stationary. The estimated multiple structural break dates in the stock prices corresponds with devaluation of Fijian dollar by 20 percent in 2009 and General Elections in September 2014, which Fiji First Party won by majority votes. The empirical results indicate that stock prices are best characterized as a unit root (random walk) process, indicating that the weak-form efficient market hypothesis holds in Fiji’s stock market. Hence, it will be difficult to predict future returns based on historical movement of stock prices in Fiji’s stock market.


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