Khóa luận tốt nghiệp impact of covid 19 on vietnams stock market

iv TABLE OF CONTENTS ABSTRACT i DECLARATION ii ACKNOWLEDGMENT iii TABLE OF CONTENTS iv LIST OF ABBREVIATIONS vii LIST OF TABLES vii LIST OF FIGURES vii CHAPTER RESEARCH OVERVIEW 1.1 Introduction .1 1.2 Research situation related to the thesis content 1.3 Research objectives 1.3.1 Overall objective 1.3.2 Specific objectives .3 1.4 Research questions 1.5 Research subject and scope of study 1.5.1 Research subject 1.5.2 Scope of the research 1.6 Research methods .4 1.7 Thesis structure CHAPTER LITERATURE REVIEW 2.1 Theoretical basis .7 2.1.1 Securities market v 2.1.2 Stocks 2.2 Related theories 10 2.2.1 The theory efficient market .11 2.2.2 The theory of behavioral finance 12 2.2.3 The random walk theory of stock prices 12 2.3 Review of previous studies .13 2.3.1 Studies in the world 13 2.3.2 Studies in Vietnam 17 CONCLUSION OF CHAPTER 24 CHAPTER RESEARCH MODEL 25 3.1 Research model .25 3.2 Research hypothesis 29 CONCLUSION OF CHAPTER 31 CHAPTER RESEARCH DATA 32 4.1 Overview of the impact of the COVID-19 pandemic on the international market 32 4.2 Overview of the impact of the COVID-19 pandemic on Vietnam's stock market 33 4.3 Research data 36 CONCLUSION OF CHAPTER 37 CHAPTER RESEARCH RESULTS 38 5.1 Research results 38 5.2 Discuss the results 40 5.2.1 The first event: On March 30, 2020 41 vi 5.2.2 The second event: On July 28, 2020 43 5.2.3 The third event: On July 9, 2021 .44 5.3 Hypothesis testing 45 CONCLUSION CHAPTER .48 CHAPTER CONCLUSIONS AND RECOMMENDATIONS .49 6.1 Conclusions .49 6.2 Recommendations 50 REFERENCES 52 APPENDICES 56 Appendix 1: 30 firms that were in the VN30 basket at the time of the research 56 Appendix 2: Results of abnormal return and cumulative abnormal return 57 Appendix 3: Hypothesis testing .59 vii LIST OF ABBREVIATIONS Abbreviations Definition ADB Asian Development Bank AR Abnormal Returns CAR Cumulative Abnormal Returns GDP Gross Domestic Product ODV Open Development Vietnam WHO World Health Organization LIST OF TABLES Table 2.1: Previous research results 20 Table 5.1: Abnormal returns (AR) and t-test results for three lockdown times due to COVID-19 in Vietnam 40 Table 5.2: Cumulative abnormal returns (CAR) and t-test results for three lockdowns due to COVID-19 in Vietnam .41 LIST OF FIGURES Figure 3.1: Event window 29 Figure 5.1: The cumulative abnormal return (CAR) findings for Event .38 Figure 5.2: The cumulative abnormal return (CAR) findings for Event .39 Figure 5.3: The cumulative abnormal return (CAR) findings for Event .39 CHAPTER RESEARCH OVERVIEW 1.1 Introduction The outbreak and spread of the novel coronavirus disease (COVID-19) worldwide has severely affected production and people's lives in general Economies around the world are currently facing serious challenges due to the COVID-19 outbreak Due to fear and uncertainty, and to a reasonable assessment that corporate profits are likely to be lower due to the impact of COVID-19, the global stock market has erased about $6 trillion in wealth for the week from February 24 to February 28, 2020 Particularly for the Vietnamese stock market, right in the first outbreak of the outbreak, the VN-Index decreased by 36% in value compared to the end of 2019 (1024 points down to 650 points) He et al (2020) believes that the impact of COVID-19 on the economy is not the cyclical volatility of traditional economic development The short-term catastrophes caused by the pandemic also surpass any endogeneity and extreme events of the past Assessing and understanding the economic impact of COVID-19 has become a critical issue The traditional economic and financial theory holds that stock prices are affected by market and firm characteristic-based factors Companies in the same industry face the same regulatory and policy environment and similar macroeconomic conditions When faced with changes in the economic environment, the operating conditions of companies in the same industry are highly correlated (Moskowitz & Grinblatt, 1999) According to the theory of behavioral finance, in addition to the basic value of stocks, emergencies will have an impact on investors’ psychological and behavioral factors, which in turn will have an important impact on stock prices Lee and Jiang (2002) believe that investor optimism will reduce earnings volatility, while investor pessimism will increase earnings volatility Therefore, the outbreak of COVID-19 will have an impact on the economic environment, which will affect investor sentiment, causing stock price changes (He et al., 2020) The COVID-19 pandemic, a public health emergency, has not only caused infection and death to people but also disrupted the stock market Vietnam is one of the countries responding most effectively to COVID-19 As soon as COVID-19 was reported, the Government convened and promptly adopted blockade regulations to stop the disease's spread As the pandemic spreads, new policies are established Research on the impact of the COVID-19 pandemic on the Vietnamese economy and the stock market has been widely publicized Specifically, the study of Vo Duc Tam & Vo Van Ban (2021) and the study of Lai Cao Mai Phuong (2021) However, most studies in Vietnam only study the period before and during the pandemic outbreak, and research activities are only researched for each industry, so there is no general overview of the whole market Different industries are affected by the pandemic to varying degrees, and their ability to respond varies To comprehensively assess the impact of COVID-19 on the stock prices in Vietnam, the author decided to apply the Event Study method to examine the stock prices of these companies Therefore, the topic "Impact of COVID-19 on Vietnam's stock market" was selected by the author for the thesis 1.2 Research situation related to the thesis content According to He et al (2020), In the capital market, emergencies often affect investor behavior by affecting investor sentiment, which ultimately affects stock prices The earliest event study proposed by Fama et al (1969) can be used to understand whether market security prices are related to specific events In recent years, event study has been widely used in the field of accounting and financial practice and has gradually become a common research method in business studies Up to this point, many domestic and foreign authors have conducted research on the impact of COVID-19 on the stock market In China, He et al (2020) pointed out that the COVID-19 pandemic seriously affected China's traditional industries (transportation, mining, electricity & heating, and the environment), but it creates opportunities for high-tech sectors to develop, such as the manufacturing industry, information technology, education, and healthcare Alam et al (2021) show that, on February 27, 2020, after the announcement of the COVID-19 outbreak in Australia, the food, pharmaceutical, and healthcare industries had an unusual return, which is impressively positive However, 10 days after the announcement of the event, the transportation sector performed poorly, while the telecommunications, pharmaceutical, and healthcare sectors performed well In Vietnam, Lai Cao Mai Phuong (2021a) researched the banking sector index 250 days before each event and has shown that the stock price movements of the banking sector react differently to each event However, research studies in Vietnam focus primarily on examining the impact of COVID-19 on each specific industry Studies in Vietnam often not analyze broadly across all sectors Therefore, this study will continue to inherit, update, and study the impact of the COVID-19 epidemic on the stock prices of companies in the Vietnamese stock market 1.3 Research objectives 1.3.1 Overall objective The goal of the study was to examine how the COVID-19 pandemic affected the stock values on the Vietnamese stock market On that premise, the author up with some suggestions to assist investors in making more sane investing choices 1.3.2 Specific objectives  Impact of COVID-19 on Vietnam's stock market  Stock prices are reflective of published information related to COVID-19  Proposing solutions to assist investors in limiting risks when making stock market investment decisions 1.4 Research questions Question How does the COVID-19 pandemic affect the Vietnamese stock market? Question How does the stock price reflect the published information related to COVID-19? Question What recommendations should be given to help investors minimize risks when making investment decisions on the stock market? 1.5 Research subject and scope of study 1.5.1 Research subject The COVID-19 pandemic and stock prices of firms listed on the Vietnamese stock exchange 1.5.2 Scope of the research Regarding space: Share prices of companies in the VN30 index Regarding time: The period from September 2019 to April 2021 1.6 Research methods In this thesis, the author uses the Event Study method The event method uses a measure of the extraordinary returns arising from events Through the value of extraordinary earnings, it is possible to estimate the market's response to changes in stock prices or measure changes in the performance of a business when significant events occur An event is defined as an action or phenomenon related to an organization that is made available to the public Events are usually divided into two types: random events (natural disasters, epidemics, wars ) and regular events (business announcements, dividend payments ) In this study, the COVID-19 outbreak was a random event Specifically, three times that the Government announced social distancing information The first time was on March 30, 2020, when the Government issued a directive to implement nationwide social distancing; the second time was on July 28, 2020, when announcing information on implementing social distancing in Da Nang; the third time was on July 2021 when Ho Chi Minh City applies directive 16 These three days were chosen because they showed that the number of COVID-19 cases grew fast and there was infectiousness in the population If the COVID-19 outbreak is not contained quickly, it will represent a major threat to public health and have far-reaching implications This thesis uses the Event Study method developed by Fama et al (1969) This is the main methodology to examine the reaction of industry price indexes on the Vietnamese stock market in response to social blockade events because of the COVID-19 epidemic As a result, the study will be structured in accordance with the steps and standards of the event study methodology In an event study, the author follows four processes to assess an event's impact: Step 1: Identify interesting events Step 2: Model how stock prices react to events Step 3: Calculate abnormal returns and cumulated abnormal returns Step 4: Use t-distribution statistics (t-statistics test) to check how the COVID-19 epidemic in Vietnam affects stock prices The t-statistics were calculated at different time points in each event window 1.7 Thesis structure CHAPTER RESEARCH OVERVIEW CHAPTER LITERATURE REVIEW CHAPTER RESEARCH MODEL CHAPTER RESEARCH DATA CHAPTER RESEARCH RESULTS CHAPTER CONCLUSIONS AND RECOMMENDATIONS 50 lockdown in Da Nang was much smaller than the first lockdown event across Vietnam at the end of March 2020 At the third event, when Ho Chi Minh City, one of the country's key economies accounting for 22% of the country's GDP, announced a lockdown, to limit the spread of coronavirus This has greatly affected the supply chain and business results of businesses, especially those in the South The research has shown that stock prices tend to decrease in the first and third events and tend to increase in the second event This study contributes to the previous literature on the impact of the epidemic on the stock prices of companies listed on the Vietnamese stock market, the sample selected for the research stocks in the VN30 index It considered the full impact of all three events related to the impact of the COVID-19 epidemic in 2020 and 2021 in Vietnam on the stock market An important market for the nation's businesses and economy It also clarifies the timely responses and decisions of Vietnamese leaders to achieve the dual goal of both fighting the COVID-19 pandemic and supporting businesses to recover soon after the pandemic 6.2 Recommendations In the face of the undeniable adverse effects of the COVID-19 pandemic, it has also caused significant impacts on the business activities of businesses as well as the entire economy Meanwhile, during the outbreak of COVID-19 in Vietnam, the number of investors opening new securities accounts increased at a record speed The main reason comes from the Government's social blockade policy, causing the real estate market to freeze, banks cutting interest rates to support businesses in difficulty due to COVID-19, causing savings interest rates to decrease This has led to massive cash flow being pushed into the stock market And the stock market has appeared many new investors New individual investors (F0) are mainly amateurs, so even though they participate in large numbers, they have a lower degree of portfolio diversification, and a smaller trading size and volume compared to other institutional investors Individual investors often not have a long-term 51 investment strategy and not follow specific investment philosophies Therefore, based on research results on the impact of COVID-19 on Vietnam's stock market, this study offers some implications for investors Firstly, during the COVID-19 pandemic, some businesses have a high risk of increasing bad debt, and unusually large-scale withdrawals can cause corporate crises or even bankruptcy Therefore, investors should learn carefully about investment enterprises before making investment decisions to avoid making wrong decisions when investing in businesses that are not good or have no growth potential Secondly, before each investment decision, investors need to update information, especially information that is likely to have a strong impact on the economy and the stock market (such as the evolution of the COVID-19 epidemic), to analyze and have a timely response strategy Investors need to pay close attention to quickly check official information and its developments Keeping up to date with current events along with correct information handling in the market is essential This will help investors seize investment opportunities to gain profits or minimize losses Thirdly, investors when investing in the stock market during this period Especially for new investors (F0), need to be very careful with misleading information to preserve profit margins and minimize investment risks 52 REFERENCES VIETNAMESE Open Development Vietnam, 2020 Timeline of COVID -19 and Vietnam policy actions at a glance [Online] Available at: https://vietnam.opendevelopmentmekong.net/vi/stories/timeline-ofcovid-19-and-vietnam-policy-actions-at-a-glance/ [Accessed 18 10 2022] State Securities Commission of Vietnam, 2019 Law on Securities [Online] Available at: https://thuvienphapluat.vn/van-ban/Chung-khoan/Luat-Chung-khoannam-2019-399763.aspx [Accessed 10 2022] Vo Duc Tam & Vo Van Ban, 2021 Impact of the Covid-19 pandemic on Retail stocks Industry and Trade magazine, Issue ENGLISH Alam, M M., Wei, H & Wahid, A N M., 2021 COVID-19 outbreak and sectoral performance of the Australian stock market: An 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56 APPENDICES Appendix 1: 30 firms that were in the VN30 basket at the time of the research Number Stock Free-Float (%) Number of shares outstanding (share) Market capitalization (billion VND) ACB 85,00% 3.377.435.134 68.899,68 BID 5,00% 5.058.523.776 164.907,88 CTG 15,00% 4.805.750.653 104.044,50 GVR 5,00% 4.000.000.000 60.400,00 BVH 10,00% 742.322.764 35.668,61 FPT 85,00% 1.091.294.390 81.070,26 PLX 10,00% 1.270.296.099 40.023,66 GAX 5,00% 1.913.950.000 205.175,44 HDB 70,00% 2.505.039.160 41.501,81 10 HPG 55,00% 5.814.785.700 98.269,88 11 POW 25,00% 2.341.871.600 24.121,28 12 KDH 65,00% 703.422.152 17.096,40 13 MBB 55,00% 4.533.986.161 72.997,18 14 MSN 45,00% 1.417.074.447 106.494,61 15 TCB 65,00% 3.511.476.908 80.544,76 16 MWG 70,00% 1.449.381.835 79.617,22 17 NVL 40,00% 1.934.234.703 146.237,54 18 PDR 40,00% 670.912.886 32.709,17 19 PNJ 85,00% 231.683.357 25.756,42 20 VIC 25,00% 3.868.111.144 216.631,54 21 SAB 11,00% 641.281.186 123.767,27 22 SSI 70,00% 1.110.380.604 24.124,05 23 STB 100,00% 1.880.231.338 30.069,19 24 TPB 50,00% 1.590.771.529 31.793,29 25 VCB 11,00% 4.732.516.523 321.811,13 26 VHM 30,00% 4.348.200.803 208.791,92 27 VJC 50,00% 541.611.334 58.981,47 28 VNM 40,00% 2.089.349.467 160.926,57 29 VPB 70,00% 6.686.954.035 104.390,32 30 VRE 40,00% 2.272.318.400 54.535,64 57 Appendix 2: Results of abnormal return and cumulative abnormal return Results of abnormal return (AR) t 30/03/2020 28/07/2020 09/07/2021 AR t-test AR t-test AR t-test -15 0,009 1,752* -0,014 -4,732*** 0,009 2,175** -14 0,002 0,321 0,005 2,351** -0,004 -1,191 -13 -0,003 -0,868 0,008 2,819*** 0,004 1,342 -12 0,007 1,753* -0,022 -7,541*** -0,004 -0,981 -11 0,004 0,915 -0,005 -3,449*** 0,000 -0,032 -10 0,001 0,186 -0,005 -1,846* 0,009 2,628** -9 0,006 0,928 0,004 2,271** 0,010 3,165*** -8 -0,005 -1,229 0,011 5,087*** 0,000 0,068 -7 0,006 1,716* -0,011 -5,263*** -0,005 -1,46 -6 0,015 2,277** -0,020 -7,14*** 0,007 2,727** -5 0,007 1,614 -0,016 -5,984*** 0,005 1,313 -4 0,008 1,225 -0,010 -4,879*** -0,006 -1,095 -3 -0,010 -2,339** 0,015 4,938*** -0,045 -7,092*** -2 -0,018 -2,573** -0,033 -14,338*** 0,017 1,987* -1 -0,014 -2,564** -0,056 -16,075*** -0,010 -2,505** 0,004 0,858 0,027 7,196*** -0,023 -4,805*** -0,003 -0,589 -0,036 -5,544*** -0,047 -4,775*** -0,002 -0,45 0,021 8,402*** -0,001 -0,282 -0,003 -0,757 0,002 0,766 -0,020 -4,014*** -0,006 -1,513 0,040 9,074*** 0,008 2,225** -0,004 -0,775 0,020 9,174*** 0,002 0,804 0,000 -0,016 0,016 7,069*** -0,046 -10,639*** -0,009 -1,679 0,005 1,823* 0,023 6,505*** 0,000 0,09 -0,001 -1,095 -0,007 -2,94*** 0,001 0,171 0,010 4,44*** 0,015 5,494*** 10 0,006 1,216 0,005 1,786* -0,021 -6,572*** 11 0,003 0,734 0,010 5,346*** 0,000 -0,124 12 -0,002 -0,64 0,012 6,319*** 0,005 1,881* 13 0,000 -0,147 -0,001 -0,4 -0,004 -1,91* 14 -0,005 -1,123 0,002 1,162 0,011 6,046*** 15 -0,003 -0,848 -0,014 -6,775*** 0,012 3,39*** 58 Results of cumulative abnormal return (CAR) 30/03/2020 [-t;0) 28/07/2020 09/07/2021 CAR t-test CAR t-test CAR t-test -15 0,013 0,881 -0,147 -11,609*** -0,012 -0,579 -14 0,005 0,314 -0,133 -12,834*** -0,021 -1,166 -13 0,003 0,211 -0,138 -13,059*** -0,016 -0,929 -12 0,006 0,437 -0,147 -13,455*** -0,021 -1,237 -11 -0,001 -0,038 -0,125 -13,084*** -0,016 -1,052 -10 -0,005 -0,285 -0,12 -12,561*** -0,016 -1,034 -9 -0,006 -0,361 -0,115 -11,577*** -0,025 -1,623 -8 -0,012 -0,946 -0,119 -12,642*** -0,035 -2,307** -7 -0,007 -0,567 -0,131 -14,429*** -0,035 -2,445** -6 -0,013 -1,038 -0,12 -12,981*** -0,031 -2,385** -5 -0,028 -2,106** -0,1 -12,261*** -0,038 -3,037*** -4 -0,035 -2,519** -0,083 -11,853*** -0,043 -3,715*** -3 -0,042 -3,081*** -0,074 -12,738*** -0,037 -3,31*** -2 -0,032 -2,879*** -0,088 -17,86*** 0,007 0,753 -0,005 -0,612 -0,015 -2,173** -0,048 -4,589*** -0,008 -0,846 -0,013 -1,508 -0,069 -5,096*** -0,013 -1,269 0,027 2,821*** -0,061 -4,429*** -0,017 -1,413 0,047 4,381*** -0,058 -4,026*** -0,017 -1,289 0,063 6,113*** -0,105 -6,081*** -0,027 -1,922* 0,068 6,149*** -0,081 -4,797*** -0,026 -1,846* 0,067 6,078*** -0,089 -5,185*** -0,026 -1,779* 0,077 6,883*** -0,074 -4,066*** 10 -0,02 -1,295 0,082 6,58*** -0,095 -4,856*** 11 -0,017 -1,122 0,092 6,827*** -0,095 -4,251*** 12 -0,019 -1,18 0,104 7,285*** -0,09 -3,998*** 13 -0,02 -1,13 0,103 6,802*** -0,094 -4,238*** 14 -0,024 -1,236 0,105 6,697*** -0,083 -3,778*** 15 -0,027 -1,375 0,091 6,355*** -0,07 -3,415*** 59 Appendix 3: Hypothesis testing Check for the existence of AR Results of the first event t-test t 30/03/2020 Sig (2-tailed) AR t-test Hypothesis testing -15 0,009 1,752* 0,090 Reject H0 -14 0,002 0,321 0,751 Do not reject H0 -13 -0,003 -0,868 0,393 Do not reject H0 -12 0,007 1,753* 0,090 Reject H0 -11 0,004 0,915 0,368 Do not reject H0 -10 0,001 0,186 0,854 Do not reject H0 -9 0,006 0,928 0,361 Do not reject H0 -8 -0,005 -1,229 0,229 Do not reject H0 -7 0,006 1,716* 0,097 Reject H0 -6 0,015 2,277** 0,030 Reject H0 -5 0,007 1,614 0,117 Do not reject H0 -4 0,008 1,225 0,230 Do not reject H0 -3 -0,010 -2,339** 0,026 Reject H0 -2 -0,018 -2,573** 0,015 Reject H0 -1 -0,014 -2,564** 0,016 Reject H0 0,004 0,858 0,398 Do not reject H0 -0,003 -0,589 0,560 Do not reject H0 -0,002 -0,45 0,656 Do not reject H0 -0,003 -0,757 0,455 Do not reject H0 -0,006 -1,513 0,141 Do not reject H0 -0,004 -0,775 0,444 Do not reject H0 0,000 -0,016 0,987 Do not reject H0 -0,009 -1,679 0,104 Do not reject H0 0,000 0,09 0,929 Do not reject H0 0,001 0,171 0,865 Do not reject H0 10 0,006 1,216 0,234 Do not reject H0 11 0,003 0,734 0,469 Do not reject H0 12 -0,002 -0,64 0,527 Do not reject H0 13 0,000 -0,147 0,884 Do not reject H0 14 -0,005 -1,123 0,271 Do not reject H0 15 -0,003 -0,848 0,404 Do not reject H0 60 Results of the second event t-test t 28/07/2020 Sig (2-tailed) AR t-test Hypothesis testing -15 -0,014 -4,732*** 0,000 Reject H0 -14 0,005 2,351** 0,026 Reject H0 -13 0,008 2,819*** 0,009 Reject H0 -12 -0,022 -7,541*** 0,000 Reject H0 -11 -0,005 -3,449*** 0,002 Reject H0 -10 -0,005 -1,846* 0,075 Reject H0 -9 0,004 2,271** 0,031 Reject H0 -8 0,011 5,087*** 0,000 Reject H0 -7 -0,011 -5,263*** 0,000 Reject H0 -6 -0,020 -7,14*** 0,000 Reject H0 -5 -0,016 -5,984*** 0,000 Reject H0 -4 -0,010 -4,879*** 0,000 Reject H0 -3 0,015 4,938*** 0,000 Reject H0 -2 -0,033 -14,338*** 0,000 Reject H0 -1 -0,056 -16,075*** 0,000 Reject H0 0,027 7,196*** 0,000 Reject H0 -0,036 -5,544*** 0,000 Reject H0 0,021 8,402*** 0,000 Reject H0 0,002 0,766 0,450 Do not reject H0 0,040 9,074*** 0,000 Reject H0 0,020 9,174*** 0,000 Reject H0 0,016 7,069*** 0,000 Reject H0 0,005 1,823* 0,079 Reject H0 -0,001 -1,095 0,283 Do not reject H0 0,010 4,44*** 0,000 Reject H0 10 0,005 1,786* 0,085 Reject H0 11 0,010 5,346*** 0,000 Reject H0 12 0,012 6,319*** 0,000 Reject H0 13 -0,001 -0,4 0,692 Do not reject H0 14 0,002 1,162 0,255 Do not reject H0 15 -0,014 -6,775*** 0,000 Reject H0 61 Results of the third event t-test t 09/07/2021 Sig (2-tailed) AR t-test Hypothesis testing -15 0,009 2,175** 0,038 Reject H0 -14 -0,004 -1,191 0,243 Do not reject H0 -13 0,004 1,342 0,190 Do not reject H0 -12 -0,004 -0,981 0,335 Do not reject H0 -11 0,000 -0,032 0,975 Do not reject H0 -10 0,009 2,628** 0,014 Reject H0 -9 0,010 3,165*** 0,004 Reject H0 -8 0,000 0,068 0,946 Do not reject H0 -7 -0,005 -1,46 0,155 Do not reject H0 -6 0,007 2,727** 0,011 Reject H0 -5 0,005 1,313 0,199 Do not reject H0 -4 -0,006 -1,095 0,282 Do not reject H0 -3 -0,045 -7,092*** 0,000 Reject H0 -2 0,017 1,987* 0,056 Reject H0 -1 -0,010 -2,505** 0,018 Reject H0 -0,023 -4,805*** 0,000 Reject H0 -0,047 -4,775*** 0,000 Reject H0 -0,001 -0,282 0,780 Do not reject H0 -0,020 -4,014*** 0,000 Reject H0 0,008 2,225** 0,034 Reject H0 0,002 0,804 0,428 Do not reject H0 -0,046 -10,639*** 0,000 Reject H0 0,023 6,505*** 0,000 Reject H0 -0,007 -2,94*** 0,006 Reject H0 0,015 5,494*** 0,000 Reject H0 10 -0,021 -6,572*** 0,000 Reject H0 11 0,000 -0,124 0,902 Do not reject H0 12 0,005 1,881* 0,070 Reject H0 13 -0,004 -1,91* 0,066 Reject H0 14 0,011 6,046*** 0,000 Reject H0 15 0,012 3,39*** 0,002 Reject H0 62 Check for the existence of CAR Results of the first event t-test [t;0) 30/03/2020 Sig (2-tailed) CAR t-test Hypothesis testing -15 0,013 0,881 0,386 Do not reject H0 -14 0,005 0,314 0,755 Do not reject H0 -13 0,003 0,211 0,834 Do not reject H0 -12 0,006 0,437 0,666 Do not reject H0 -11 -0,001 -0,038 0,970 Do not reject H0 -10 -0,005 -0,285 0,778 Do not reject H0 -9 -0,006 -0,361 0,720 Do not reject H0 -8 -0,012 -0,946 0,352 Do not reject H0 -7 -0,007 -0,567 0,575 Do not reject H0 -6 -0,013 -1,038 0,308 Do not reject H0 -5 -0,028 -2,106** 0,044 Reject H0 -4 -0,035 -2,519** 0,018 Reject H0 -3 -0,042 -3,081*** 0,004 Reject H0 -2 -0,032 -2,879*** 0,007 Reject H0 -0,005 -0,612 0,545 Do not reject H0 -0,008 -0,846 0,404 Do not reject H0 -0,013 -1,269 0,215 Do not reject H0 -0,017 -1,413 0,168 Do not reject H0 -0,017 -1,289 0,207 Do not reject H0 -0,027 -1,922* 0,064 Reject H0 -0,026 -1,846* 0,075 Reject H0 -0,026 -1,779* 0,086 Reject H0 10 -0,020 -1,295 0,206 Do not reject H0 11 -0,017 -1,122 0,271 Do not reject H0 12 -0,019 -1,18 0,248 Do not reject H0 13 -0,020 -1,13 0,268 Do not reject H0 14 -0,024 -1,236 0,227 Do not reject H0 15 -0,027 -1,375 0,180 Do not reject H0 63 Results of the second event t-test [t;0) 28/07/2020 Sig (2-tailed) CAR t-test Hypothesis testing -15 -0,147 -11,609*** 0,000 Reject H0 -14 -0,133 -12,834*** 0,000 Reject H0 -13 -0,138 -13,059*** 0,000 Reject H0 -12 -0,147 -13,455*** 0,000 Reject H0 -11 -0,125 -13,084*** 0,000 Reject H0 -10 -0,120 -12,561*** 0,000 Reject H0 -9 -0,115 -11,577*** 0,000 Reject H0 -8 -0,119 -12,642*** 0,000 Reject H0 -7 -0,131 -14,429*** 0,000 Reject H0 -6 -0,120 -12,981*** 0,000 Reject H0 -5 -0,100 -12,261*** 0,000 Reject H0 -4 -0,083 -11,853*** 0,000 Reject H0 -3 -0,074 -12,738*** 0,000 Reject H0 -2 -0,088 -17,86*** 0,000 Reject H0 -0,015 -2,173** 0,038 Reject H0 -0,013 -1,508 0,142 Do not reject H0 0,027 2,821*** 0,009 Reject H0 0,047 4,381*** 0,000 Reject H0 0,063 6,113*** 0,000 Reject H0 0,068 6,149*** 0,000 Reject H0 0,067 6,078*** 0,000 Reject H0 0,077 6,883*** 0,000 Reject H0 10 0,082 6,58*** 0,000 Reject H0 11 0,092 6,827*** 0,000 Reject H0 12 0,104 7,285*** 0,000 Reject H0 13 0,103 6,802*** 0,000 Reject H0 14 0,105 6,697*** 0,000 Reject H0 15 0,091 6,355*** 0,000 Reject H0 64 Results of the third event t-test [t;0) 09/07/2021 Sig (2-tailed) CAR t-test Hypothesis testing -15 -0,012 -0,579 0,567 Do not reject H0 -14 -0,021 -1,166 0,253 Do not reject H0 -13 -0,016 -0,929 0,361 Do not reject H0 -12 -0,021 -1,237 0,226 Do not reject H0 -11 -0,016 -1,052 0,301 Do not reject H0 -10 -0,016 -1,034 0,310 Do not reject H0 -9 -0,025 -1,623 0,115 Do not reject H0 -8 -0,035 -2,307** 0,028 Reject H0 -7 -0,035 -2,445** 0,021 Reject H0 -6 -0,031 -2,385** 0,024 Reject H0 -5 -0,038 -3,037*** 0,005 Reject H0 -4 -0,043 -3,715*** 0,001 Reject H0 -3 -0,037 -3,31*** 0,003 Reject H0 -2 0,007 0,753 0,457 Do not reject H0 -0,048 -4,589*** 0,000 Reject H0 -0,069 -5,096*** 0,000 Reject H0 -0,061 -4,429*** 0,000 Reject H0 -0,058 -4,026*** 0,000 Reject H0 -0,105 -6,081*** 0,000 Reject H0 -0,081 -4,797*** 0,000 Reject H0 -0,089 -5,185*** 0,000 Reject H0 -0,074 -4,066*** 0,000 Reject H0 10 -0,095 -4,856*** 0,000 Reject H0 11 -0,095 -4,251*** 0,000 Reject H0 12 -0,090 -3,998*** 0,000 Reject H0 13 -0,094 -4,238*** 0,000 Reject H0 14 -0,083 -3,778*** 0,001 Reject H0 15 -0,070 -3,415*** 0,002 Reject H0 ... with COVID- 19 related information 18 The impact of COVID- 19 on stock price: An application of the event study method in Vietnam (Lai Cao Mai Phuong, 2021b) This article examines how the COVID- 19... abnormal rate of return during the window period 14 The impact of the COVID- 19 pandemic on the market value of 18 subsectors in China On the day of the COVID- 19 outbreak, the stock prices of the agriculture,... impact of COVID- 19 on the stock prices in Vietnam, the author decided to apply the Event Study method to examine the stock prices of these companies Therefore, the topic "Impact of COVID- 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