The Act regarding the Exercise of Shareholders’ Rights for Shareholders in Mainland China of a Company in Taiwan Article 5

The dividends and other profits of the reserved shares shall be saved in a special account of each of a Company in Taiwan before the unification of the nation.When a Company in Taiwan issues new shares, Shareholders in Mainland China shall have no right to subscript new shares before the unification of the nation.
中文原文 在臺公司大陸地區股東股權行使條例第5條
保留股之股利或其他收益,在國家統一前,以保留股專戶存儲於各該公司。
國家統一前,在臺公司以現金增資發行新股,大陸地區股東無新股認購權利。

English translation for reference only; the Chinese text prevails. Not legal advice.