Regulations Governing Borrowing or Lending Money in Connection with Securities Business by Securities Firms Article 13

A securities firm that conducts securities business money lending may charge its customers interest and processing fees on the loans; the interest rate shall be calculated on a per annum basis, and be posted at its place of business.
中文原文 證券商辦理證券業務借貸款項管理辦法第13條
證券商辦理證券業務借貸款項,得向客戶收取借貸款項之利息及手續費,其利率應以年率為準,並於營業埸所揭示。

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