Violation of the principle of equality of shareholders. Because of the correlation between the interests of the parent company and the subsidiary company, the subsidiary company often has an advantage over other shareholders when purchasing the shares of the parent company, thus making the status of shareholders unequal. The acquisition of shares of the parent company by subsidiaries may encourage share manipulation and insider trading, which violates the principle of fairness in share trading. When a subsidiary holds more than half of the voting shares or capital of the parent company, or it may directly or indirectly affect the personnel, finance or future operation of the other company, the parent-subsidiary company will evolve into a mutually controlled parent-subsidiary company. At this time, it is easy for senior managers of parent-subsidiary companies to conduct transactions, and it is also easy for directors and supervisors to stay permanently.