Research findings clarified following set targets:
Firstly, Investors’ reaction is expressed through stock price and stock trading volume when the announcement of stock transaction registration of internal shareholders.
Information contained in the announcement of stock purchase registration of internal shareholders is considered good information for the market and the internal shareholders may implement stock purchase behavior as one important strategy to partially prevent the trend of decrease in stock price in the market. Stock price immediately reverse to increase when the information of stock purchase registration of internal shareholders is announced and followed the sudden increase in the trading volume surround this event date.
The information contained in announcement of stock sell registration of internal shareholders is considered bad information to the market. Stock price drops and the trend of price decrease is formed at the date of announcement of stock sell registration of internal shareholders, trading volume extraordinarily increase at days around the event date.
Secondly, Investors’ reaction is expressed through stock price and stock trading volume when the announcement of stock transaction registration of stakeholders:
(i) Personal stakeholders
Information contained in announcement of stock purchase registration of personal stakeholders is considered good information. Stock price increases and new price is formed.
Trading volume extraordinarily increases from the date information is announced and maintains later days. There is a symptom that other investors implement transactions or the transactions increases according to the one of stakeholders.
Investors’ reaction is similar to the case of stock sell registration of internal shareholders, the market considers the information of stock sell registration of personal stakeholders a bad signal.
Stock price drops and new price is formed lower after the event. Trading volume significantly fluctuates before, during and after event.
(ii) Organizational stakeholders
Information contained in announcement of stock purchase registration of organizational stakeholders is considered good information, stock price increases from the event is announced and new price is formed after the event. Trading volume increases but not obviously.
The information contained in announcement of stock sell registration of organizational stakeholders is bad information. Stock price immediately decreases and forms a trend of decrease in stock price from the announcement date. Trading volume extraordinarily increases before, during and after event.
Thirdly, Investors’ reaction is expressed through stock price and stock trading volume to the influence from information of foreign investors become majority shareholders or no longer majority shareholders:
(i) Event of foreign investors become majority shareholders
The disclosure date of foreign investors to become majority shareholders. There was no statistical evidence on investors reaction expressed through trading volume before and at the
disclosure date of event that foreign organizations become majority shareholders of the company.
The event didn't contain or convey signal to the market.
The transaction date of foreign investors to become majority shareholders. Date of foreign investors’ purchasing stocks to become majority shareholders has impact on stock price, stronger the purchasing power is and higher volume is, the higher stock price is. Escalation of price is purely due to rule of supply and demand.
(ii) Event of foreign investors become no longer majority shareholders
The announcement date of stock sell registration of foreign investors become no longer majority shareholders. There was no obvious impact on stock price and stock trading volume on the market. The event neither contained information.
The date of stock sell registration of foreign investors become no longer majority shareholders. There was inadequate evidence showing that the information contained in stock sell of foreign investors is bad information. Stock price didn't abnormally fluctuate before and at the event date. Abnormal big trading volume around the event date.
7.2. Implied policies Investors
Some implications for investors include:
Firstly, investors may purchase stock or continue to hold stock according to purchase registration transaction of internal shareholders and stakeholders.
Secondly, shortterm investors should consider selling stock or decreasing stock holding density with information related to stock sell registration announcement of internal shareholders and stake holders (personal, organizational).
Thirdly, investors shouldn’t rely on stock sell, purchase transaction information of foreign investors to become majority shareholders or no longer majority shareholder for business.
For managers
Firstly, managers need to well control and have satisfactory sanctions for violations in disclosing transaction information of internal shareholders and stakeholders.
Secondly, managers need to have policies on management, control and strict treatment for intentional behaviors of revealing information and collusion between internal shareholders with other financial organizations for making stock price.
Thirdly, managers, controllers of the disclosing correct information related to fluctuations of majority shareholders including foreign investors.
7.3. Scientific and practical contribution 7.3.1. Scientific contribution
Although applications of event study methodology in economic were studied by authors with different events, the studies actually done on samples of foreign markets, moreover, study on impact of the information of stock transaction registration of internal shareholders, stakeholders and information that foreign investors become majority shareholders and no longer majority shareholders has never been studied by scientists. Therefore, this is a new study contributing to the academic treasure.
7.3.2. Practical contribution
Study findings of the thesis create one more experimental evidence on: i) impact of the information of stock transaction registration of internal shareholders; ii) effect of the information on stock transaction registration of stakeholders on security market; and iii) impact of the information that foreign investors become majority shareholders and no longer majority shareholders on security market from that help investors to make appropriate decisions. How investors should react on the information of stock transaction of internal shareholders, stakeholders and majority shareholders being foreign investors since then help to make an investment decision for the best efficiency.
For market managers, the subject studies on whether there is or not information reveal before stock transaction registration date of internal shareholders, stakeholders and majority shareholders being foreign investors which is disclosed. This helps market managers and supervisors to work out strict regulations and hard sanctions for violations of confidentiality, insider trading regulations.
Especially, alone trading related to internal shareholders and stakeholders for nonappropriate nature of information, securities market management agencies also need to closely supervise stock transaction of these shareholders in order to protect other shareholders creating equality and transparency for Vietnam securities market.
7.4. Shortcomings
In spite of making best endeavors to complete the thesis, we can't avoid some following shortcomings:
Firstly, besides the considered events, there may be existence at the same time of other events that has impact on stock price and stock trading volume. However, the study has not have solutions. This is also considered a outstanding particular shortcoming of the event study methodology;
Secondly, the study has not mentioned how the factor of features of the company has impact on price fluctuation and trading volume corresponding to each studied event.
Thirdly, new point of the thesis is also a limitation, the thesis topic studied has not previous studies available. In spite of having attempted to refer studies posted on domestic and foreign articles, similar thesis in the world. However, no previous studies of the same topic have not been found. Therefore, the study findings are lack of comparison with previous studies;
Fourthly, there was not supporting software and the data of the project were manually processed. At present, there is supporting software for event study methodology application called Event Study Metrics, however, it is designed to process information from https://finance.yahoo.com/. Thus, application in cases in Vietnam is now unrealizable. Besides, some supporting softwares such as Stata, however, preprocessing sections before applying to Stata is also very complicated, completely manually treated and Stata only helps inspection run.
Therefore, to the thesis implementing time, the data processing was totally manual.
7.5. Next studies
Based on the shortcomings of the thesis, following study orientation is recommended:
Firstly, besides consideration impact of information, price and trading volume events, the factors of features of the company should be considered: market capitalization, profitability (ROE, ROA), degree of financial leverage or administration structure of company, etc. how they have impact on price and trading volume;