In order to protect the interests of small and medium-sized investors and prevent large investors from manipulating the stock price, the Securities Law stipulates that when investors and their concerted actions hold 5% of the issued shares of a listed company, they shall make a written report to the the State Council securities regulatory body and the stock exchange within 3 days from the date of the fact, notify the listed company and make an announcement, and fulfill their obligations stipulated by relevant laws. The Measures for the Administration of the Acquisition of Listed Companies has made more specific provisions on the contents and methods of reports and announcements, and the trading restrictions during the announcement period. Every time a share purchase reaches 5%, it will be announced to the public, commonly known as "placarding".