The calculation formula is:
Ex-dividend price of allotment = (closing price on ex-dividend date+allotment price * allotment ratio per share) /( 1+ allotment ratio per share)
Another formula is:
Ex-dividend price of rights issue = (closing price on base date * original total share capital+current share issue price * share issue capital)/(original total share capital+share issue capital) (Shenzhen Stock Exchange)
This means that only some shareholders participate in the rights issue, and state-owned or legal person shareholders give up part of the rights issue.
Therefore, investors should carefully read the prospectus and make calculations according to different situations, so as to make reasonable investment choices.