The Act Governing Bills Finance Business Article 5

A Bills House shall not certify, underwrite, broker or trade, an issuer's Short-Term Bills that are not rated by a credit rating agency except for the following which are exempt from this rating requirement;1. Treasury notes;2. Commercial papers or bills of exchange endorsed by the recipient as part of the sale of goods or services; and3. Short-Term Bills guaranteed by a financial institution which institution is rated by a credit rating agency.
中文原文 票券金融管理法第5條
票券商不得簽證、承銷、經紀或買賣發行人未經信用評等機構評等之短期票券。
但下列票券,不在此限:
一、國庫券。
二、基於商品交易或勞務提供而產生,且經受款人背書之本票或匯票。
三、經金融機構保證,且該金融機構經信用評等機構評等之短期票券。

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