Administrative Regulations for Number Portability Services of Telecommunications Enterprises Article 24

Operators shall bear the establishment and maintenance cost necessary for providing Number Portability.
中文原文 電信事業號碼可攜服務管理辦法第24條
經營者為提供號碼可攜服務所需之建置及維護成本,應自行負擔之。

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