After full circulation, if the stock rises sharply, will the listed company cash in at a high price and buy at a low price? Become a new generation of bookmakers? What are the rules in this country?

Very, but major shareholders usually need the approval of the board of directors to buy and sell stocks, especially if the number of transactions exceeds 5%. Generally speaking, in a well-developed enterprise, the major shareholder will not cash out easily. Unless it does not affect its absolute controlling interest in the enterprise, it may endanger the status of the major shareholder, depending on the different regulations of different companies.