Why did the share price fall after dividends?

It is not a simple decline, but its stock ex-dividend is due to the fact that listed companies distribute dividends to investors, which reduces the actual value (net assets per share) of the enterprise represented by each share. Therefore, it is necessary to remove these factors from the stock market price after distribution, and the sum of the stock market value after ex-dividend and dividend should be equivalent to the stock price before ex-dividend. All the shares to be distributed (distribution scheme includes share offering, capitalization, allotment and dividend) need to be ex-dividend or ex-dividend.